Talk:Human Physiology/Nutrition

General discussion on level of appropriate detail
Can we have a table on micronutrients? That would totally fit in and be easily read. Dannette? Can you do that?

K who took out all of the info I spent all day putting in on micronutrients see this is why I hate this stuff.

The parts cut out are pasted back here.

Dont we neeed this to be a little hard I mean it is a phys class.

The only reason why those things were moved was because we were repeating ourselves so many times.. we had vitamins listed 3 times. The deleted parts are pasted down below.. so they can be brought back to fit in what is already there. Sorry I did that.. really thought it was for the best. ;-)


 * I agree that there was a repeat of information. We need to come up with a nicely organized way to present the information. Deciding what is an appropriate level of detail is always tough. We want enough information so people learn new things and are challenged, but we don't want to drown the reader in detail. For vitamins and minerals, what types of information do we want to include--the actions of the micronutrient in the body, good sources of the micronutrient in foods, disease conditions that result from lack of the micronutrient? Is it best in a table or a list? I appreciate the work everyone is doing. Sorry for the frustrations, but I think this is a valuable process. Provophys 03:55, 5 April 2007 (UTC)


 * which type of drought are we talking about? 41.116.155.172 (discuss) 20:57, 17 April 2023 (UTC)
 * you can give me a deep information 41.116.155.172 (discuss) 20:58, 17 April 2023 (UTC)

Thank you that helps to know how much detail we should go into.

PLEASE VOTE: Do we want these tables?
I took these tables out of the protein section (from the old chapter portion). I moved them here, for now, and you can vote to keep them or not. To vote, just put four tildas (the squiggle thing next to the "1" that looks like ~). When you put four in a row, it signs your login name and puts a date stamp, like this: Provophys 20:00, 4 April 2007 (UTC)

So, edit this paragraph and vote under either heading (put comments if you like). When there are five votes in either category a decision will be made.

Delete the table--we don't want it in this chapter
I'm voting for removal.Provophys 20:00, 4 April 2007 (UTC)

There is too much info on the table and they just take up too much space. I vote for cutting them way, way down. Or somehow summarizing the info in a more useful form.never2late 01:32, 5 April 2007 (UTC) Like how about the letter abbreviation, the name and the remarks???never2late 01:33, 5 April 2007 (UTC)

Keep the table--it is important information for the nutrition chapter
I like the tables- but I think they could be edited down some (or redone) to make them more student friendly Stephanie greenwood 21:24, 4 April 2007 (UTC)
 * Really it is a question of whether or not to include information on every single amino acid. If yes, then what information is most important. Provophys 04:02, 5 April 2007 (UTC)

Brianna made a new vitamin table and I inserted it for her- I think that it looks much better and accomplishes what we need- if it's not what we want then we can take it out Stephanie greenwood 02:48, 5 April 2007 (UTC)
 * I think the vitamin table looks good. The only issue I have is that others cannot edit any of the text (since it is included as an image). The formatting commands are tricky for a table, but if you want to send me the table as a Word file I can format it as a wikitable, which could then be editable by all. Provophys 03:25, 5 April 2007 (UTC)

So we added in new tables on vitamins and minerals- I think that they are much better! I also think that the part on the vitamin table with the problems associated with too much or too little vitamins is important- we are trying to become nurses after all and may see some of this Stephanie greenwood 15:35, 5 April 2007 (UTC)

Here is the table
Note: The pKa values of amino acids are typically slightly different when the amino acid is inside a protein. Protein pKa calculations are sometimes used to calculate the change in the pKa value of an amino acid in this situation.

Note: The Stop Codon is not an amino acid, but is included for completeness.

= Old Chapter: Feel free to use info from here if you want to =

I decided to move the old chapter here to clean things up on the module page. Feel free to take any of this information and move it up to the new chapter (this will all be deleted in a few days). Note: I removed many of the subheadings because the chapter table of contents was so huge and messy.

In 2004 Morgan Spurlock made the documentary film Super Size Me that chronicled his adventures in poor nutrition. In the film Morgan Spurlock ate three meals a day at McDonalds and quit exercising to see what effects would ensue. As you can guess, the results from his “McDiet” were nearly catastrophic. During his 30 day experiment he consumed an average of 5,000 calories per day. As a result, he gained 25 pounds (from 185lbs to 210lbs), experienced mood swings, sexual dysfunction, heart palpitations, and nearly experienced liver failure.

In this chapter we will be discussing various aspects of nutrition and relating back to some of the effects that Morgan Spurlock experienced during the filming of Super Size Me.

What is Nutrition?
Nutrition is a science which studies the relationship between diet and states of health and disease. Nutrition is also the study of foods and beverages that nourish the human body on the cellular level. Dieticians are health professionals who are specialized in this area of expertise. They are also the only highly trained health professionals able to provide safe, evidence-based and accurate dietary advice and interventions.

Between the extremes of optimal health and death from starvation or malnutrition, there is an array of disease states that can be caused or alleviated by changes in diet. Deficiencies, excesses and imbalances in diet can produce negative impacts on health, which may lead to diseases such as scurvy, obesity or osteoporosis, as well as psychological and behavioral problems. Moreover, excessive ingestion of elements that have no apparent role in health, (e.g. lead, mercury, PCBs, dioxins), may incur toxic and potentially lethal effects, depending on the dose. The science of nutrition attempts to understand how and why specific dietary aspects influence health.

Where did it all start?
Humans are believed by scientists to have evolved as omnivorous hunter-gatherers over the past 250,000 years. Early diets were primarily vegetarian with infrequent game meats and fish where available.


 * c. 475 BC: Anaxagoras states that food is absorbed by the human body and therefore contained "homeomerics" (generative components), thereby deducing the existence of nutrients.
 * c. 400 BC: Hippocrates says, "Let food be your medicine and medicine be your food."
 * The first recorded nutritional experiment is found in the Bible's Book of Daniel. Daniel and his friends were captured by the king of Babylon during an invasion of Israel. Selected as court servants, they were to share in the king's fine foods and wine. But they objected, preferring vegetables (pulses) and water in accordance with their Jewish dietary restrictions. The king's chief steward reluctantly agreed to a trial. Daniel and his friends received their diet for 10 days and were then compared to the king’s men. Appearing healthier, they were allowed to continue with their diet.
 * 1500s: Scientist and artist Leonardo da Vinci compared metabolism to a burning candle.
 * 1747: Dr. James Lind, a physician in the British navy, performed the first scientific nutrition experiment, discovering that lime juice saved sailors who had been at sea for years from scurvy, a deadly and painful bleeding disorder. The discovery was ignored for forty years, after which British sailors became known as "limeys." The essential vitamin C within lime juice would not be recognized by scientists until the 1930s.
 * 1770: Antoine Lavoisier, the "Father of Nutrition and Chemistry" discovered the details of metabolism, demonstrating that the oxidation of food is the source of body heat.
 * 1790: George Fordyce recognized calcium necessary for fowl survival.

Nutrition and health
Ill health can be caused by an imbalance of nutrients, producing either an excess or deficiency, which in turn affects body functions cumulatively. Moreover, because most nutrients are, in some way or another, involved in cell-to-cell signaling (e.g. as building block or part of a hormone or signaling 'cascades'), deficiency or excess of various nutrients affects hormonal function indirectly. Thus, because they largely regulate the expression of genes, hormones represent a link between nutrition and how our genes are expressed, i.e. our phenotype. The strength and nature of this link are continually under investigation, but observations especially in recent years have demonstrated a pivotal role for nutrition in hormonal activity and function and therefore in health.

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 * Essential Amino Acids, these are amino acids that can not be made by the human body, these include these 9:
 * Histidine
 * Isoleucine
 * Leucine
 * Lysine
 * Methionine
 * Phenylalanine
 * Threonine
 * Tryptophan
 * Valine
 * You can remember these in this “Hey It's Like Lovely Material Please Touch The Velvet”.


 * Nonessential amino acids, these include these 11:
 * Alanine
 * Arginine
 * Aspartic acid
 * Cysteine
 * Cystine
 * Glutamic acid
 * Glutamine
 * Glycine
 * Proline
 * Serine
 * Tryosine

Amino acids are water soluble and travel via the portal vein and then to the liver, primarily three amino acids are in the blood circulation on an average 20% of amino acids we consume go on anabolic reactions, and about 57% go towards catabolic reactions such as (gluconeogenesis) it is triggered by high levels of glucogon that is produced it the pancreas to stimulate the production of glucose in the liver. The other 23% are circulating as free amino acids. The liver is the primary regulator of amino acid conversions so transamination and deamination in order to in the addition to make new amino acids and proteins will be controlled by the liver. One unique thing about branched chain amino acids Leucine, Isoleucine, and Valine is that these because of their branched chain structure are the only amino acids that can be metabolized by the muscle. This occurs in only certain circumstances and can provide the muscles with energy during starvation. The liver during starvation has to provide for every cell in the body whereas, the muscle does not have to share with the rest of the body. In the case of starvation the liver is providing for energy and the body is trying to conserve it's energy use, in this time the muscles will take over and use the three branching chain essential amino acids, these are Leucine, Isoleucine, and Valine. The muscle breaks these down only for a short period of time to help with conservation of energy.

Dietary Proteins Dietary proteins fall into two categories; complete proteins and incomplete proteins. Complete proteins include ample amounts of all essential amino acids. Examples of complete proteins include meat, fish, poultry, cheese, eggs, and milk. Incomplete proteins contain some but not all of the essential amino acids required by the human body. Examples of incomplete proteins include legumes, and leafy green vegetables.

Vitamins Mineral and/or vitamin (tocotrienol and tocopherol) deficiency or excess may yield symptoms of diminishing health such as goiter, scurvy, osteoporosis, weak immune system, disorders of cell metabolism, certain forms of cancer, symptoms of premature aging, and poor psychological health (including eating disorders), among many others.

In humans, there are thirteen vitamins, divided into two groups, the four fat-soluble vitamins (A, D, E and K) and the nine water-soluble vitamins (eight B vitamins and vitamin C).

Fatty acids In addition to sufficient intake, an appropriate balance of essential fatty acids - omega-3 and omega-6 fatty acids - has been discovered to be crucial for maintaining health. Both of these unique "omega" long-chain polyunsaturated fatty acids are substrates for a class of eicosanoids known as prostaglandins which function as hormones. The omega-3 eicosapentaenoic acid (EPA) (which can be made in the body from the omega-3 essential fatty acid alpha-linolenic acid (LNA), or taken in through marine food sources), serves as building block for series 3 prostaglandins (e.g. weakly-inflammation PGE3). The omega-6 dihomo-gamma-linolenic acid (DGLA) serves as building block for series 1 prostaglandins (e.g. anti-inflammatory PGE1), whereas arachidonic acid (AA) serves as building block for series 2 prostaglandins (e.g. pro-inflammatory PGE 2). Both DGLA and AA are made from the omega-6 linoleic acid (LA) in the body, or can be taken in directly through food. An appropriately balanced intake of omega-3 and omega-6 partly determines the relative production of different prostaglandins, which partly explains the importance of omega-3/omega-6 balance for cardiovascular health. In industrialized societies, people generally consume large amounts of processed vegetable oils that have reduced amounts of essential fatty acids along with an excessive amount of omega-6 relative to omega-3.

The rate of conversions of omega-6 DGLA to AA largely determines the production of the respective prostaglandins PGE1 and PGE2. Omega-3 EPA prevents AA from being released from membranes, thereby skewing prostaglandin balance away from pro-inflammatory PGE2 made from AA toward anti-inflammatory PGE1 made from DGLA. Moreover, the conversion (desaturation) of DGLA to AA is controlled by the enzyme delta-5-desaturase, which in turn is controlled by hormones such as insulin (up-regulation) and glucagon (down-regulation). Because different types and amounts of food eaten/absorbed affect insulin, glucagon and other hormones to varying degrees, not only the amount of omega-3 versus omega-6 eaten but also the general composition of the diet therefore determine health implications in relation to essential fatty acids, inflammation (e.g. immune function) and mitosis (i.e. cell division). Chemically, fatty acids can be described as long-chain monocarboxylic acids and have a general structure of CH3(CH2)nCOOH. The length of the chain usually ranges from 12 to 24, always with an even number of carbons. When the carbon chain contains no double bonds, it is called saturated. If it contains one or more such bonds, it is unsaturated. The presence of double bonds generally reduces the melting point of fatty acids. Furthermore, unsaturated fatty acids can occur either in cis or trans geometric isomers. In most naturally occurring fatty acids, the double bonds are in the cis configuration.

Glycerides Glycerides are lipids possessing a glycerol core structure with one or more fatty acyl groups, which are fatty acid-derived chains attached to the glycerol backbone by ester linkages. Glycerides with three acyl groups (triglycerides or neutral fats) are the main storage form of fat in animals and plants An important type of glyceride-based molecule found in biological membranes, such as the cell's plasma membrane and the intracellular membranes of organelles, are the phosphoglycerides or glycerophospholipids. These are phospholipids that contain a glycerol core linked to two fatty acid-derived "tails" by ester or, more rarely, ether linkages and to one "head" group by a phosphate ester linkage. The head groups of the phospholipids found in biological membranes are phosphatidylcholine (lecithin), phosphatidylethanolamine, phosphatidylserine and phosphatidylinositol. These phospholipids are subject to a variety of reactions in the cell: for instance, polar head groups or fatty acid tails can be released from specific phospholipids through enzyme-catalyze hydrolysis to generate second messengers involved in signal transduction. In the case of phosphatidylinositol, the head group can be enzymatically modified by the addition of one to three phosphate molecules, and this constitutes another mechanism of cell signaling. While phospholipids are the major component of biological membranes, other non-glyceride lipid components like sphingolipids and sterols (such as cholesterol in animal cell membranes) are also found in biological membranes.

A biological membrane is a form of lipid bilayer, as is a liposome. Formation of lipid bilayers is a spontaneous process when the glycerophospholipids described above are placed in water. In an aqueous milieu, the polar heads of lipids tend to orient toward the polar, aqueous environment, while the hydrophobic tails tend to minimize their contact with water. The nonpolar tails of lipids (U) tend to cluster together, forming a lipid bilayer (1) or a micelle (2). The polar heads (P) face the aqueous environment. Micelles form when single-tailed amphiphilic lipids are placed in a polar milieu, while lipid bilayers form when two-tailed phospholipids are placed in a polar environment (Fig. 2). Micelles are "monolayer" spheres and can only reach a certain size, whereas bilayers can be considerably larger. They can also form tubules. Bilayers that fold back upon themselves form a hollow sphere, enclosing a separate aqueous compartment, which is the basis of biological membranes.

Micelles and bilayers separate out from the polar milieu by a process known as the "hydrophobic effect." When dissolving a nonpolar substance in a polar environment, the polar molecules (i.e. water in an aqueous solution) become more ordered around the dissolved nonpolar substance, since the polar molecules cannot form hydrogen bonds to the nonpolar molecule. Therefore, in an aqueous environment, the polar water molecules form an ordered "clathrate" cage around the dissolved nonpolar molecule. However, when the nonpolar molecules separate out from the polar liquid, the entropy (state of disorder) of the polar molecules in the liquid increases. This is essentially a form of phase separation, similar to the spontaneous separation of oil and water into two separate phases when one puts them together.

Self-organization of lipids. A lipid bilayer is shown on the left and a micelle on the right. The self-organization depends on the concentration of the lipid present in solution. Below the critical micelle concentration, the lipids form a single layer on the liquid surface and are dispersed in solution. At the first critical micelle concentration (CMC-I), the lipids organize in spherical micelles, at the second critical micelle concentration (CMC-II) into elongated pipes, and at the lamellar point (LM or CMC-III) into stacked lamellae of pipes. The CMC depends on the chemical composition, mainly on the ratio of the head area and the tail length.

Lipids Lipids play diverse and important roles in nutrition and health. Many lipids are absolutely essential for life. However, there is also considerable awareness that abnormal levels of certain lipids, particularly cholesterol (in hypercholesterolemia) and, more recently, trans fatty acids, are risk factors for heart disease and other diseases

Sugars

Glucose (Glc), a monosaccharide (or simple sugar), is one of the most important carbohydrates. The cell uses it as a source of energy and metabolic intermediate. Glucose is one of the main products of photosynthesis and starts cellular respiration. The natural form (D-glucose) is also referred to as dextrose, especially in the food industry. This article deals with the D-form of glucose (The mirror-image of the molecule is called L-glucose. Glucose is a ubiquitous fuel in biology. Carbohydrates are the human body's key source of energy, providing 4 kilocalories (17 kilojoules) of food energy per gram. Breakdown of carbohydrates (e.g. starch) yields mono- and disaccharides, most of which is glucose. Through glycolysis and later in the reactions of the Citric acid cycle (TCAC), glucose is oxidized to eventually form CO2 and water, yielding energy, mostly in the form of ATP. The insulin reaction, and other mechanisms, regulate the concentration of glucose in the blood. A high fasting blood sugar level is an indication of prediabetic and diabetic conditions.

All major dietary carbohydrates contain glucose, either as their only building block, as in starch and glycogen, or together with another monosaccharide, as in sucrose and lactose. In the lumen of the duodenum and small intestine the oligo- and polysaccharides are broken down to monosaccharides by the pancreatic and intestinal glycosidases. Glucose is then transported across the apical membrane of the entrecotes by SLC5A1 and later across their basal membrane by SLC2A2. Some of glucose goes directly to fuel brain cells and erythrocytes, while the rest makes its way to the liver and muscles, where it is stored as glycogen, and to fat cells, where it is stored as fat. Glycogen is the body's auxiliary energy source, tapped and converted back into glucose when there is need for energy. Glycogen is a polysaccharide that is the principal storage form of glucose (Glc) in animal and human cells. Glycogen is found in the form of granules in the cytosol in many cell types. Hepatocytes (liver cells) have the highest concentration of it - up to 8% of the fresh weight in well fed state, or 100–120 g in an adult - giving liver a distinctive, "starchy" taste. In the muscles, glycogen is found in a much lower concentration (1% of the muscle mass), but the total amount exceeds that in liver. Small amounts of glycogen are found in the kidneys, and even smaller amounts in certain glial cells in the brain and white blood cells. Function and regulation of liver glycogen As a carbohydrate meal is eaten and digested, blood glucose levels rise, and the pancreas secretes insulin. Glucose from the portal vein enters the liver cells (hepatocytes). Insulin acts on the hepatocytes to stimulate the action of several enzymes, including glycogen synthase. Glucose molecules are added to the chains of glycogen as long as both insulin and glucose remain plentiful. In this postprandial or "fed" state, the liver takes in more glucose from the blood than it releases.

After a meal has been digested and glucose levels begin to fall, insulin secretion is reduced, and glycogen synthesis stops. About four hours after a meal, glycogen begins to be broken down to be converted again to glucose. Glycogen phosphorylase is the primary enzyme of glycogen breakdown. For the next 8–12 hours, glucose derived from liver glycogen will be the primary source of blood glucose to be used by the rest of the body for fuel.

Sodium For most people it is recommended that they get between 500mg and 2400mg of sodium daily. Food Pyramid



Food can be a medicine or a death sentence
While exercise is very important to good health, to get into optimal shape a proper nutrition regimen must be maintained. As the old cliché goes, "You are what you eat" more specifically, your body is fueled by what you eat, and your body is built and repaired by the macronutrients you eat. Like any responsible car owner knows, if you put dirty lead-based fuel into your car or build it with bad parts it runs less smoothly, and the car is more prone to failure than if you use unleaded fuel or good parts. This is a great analogy to the human body, if you eat dirty foods, your body will not perform as well as it could and it will be prone to illness and injury.

The human body is designed, or has evolved to run well on certain fuels. Unfortunately, McDonald's French fries are not it. When considering the environment which our ancestors lived in, it is easy to see what types of foods our bodies are meant to be fed. For example, the carbohydrates that they ate were mostly berries, nuts, beans and legumes. All of these are very high in fiber and low in sugars. In contrast, the typical western diet is low in fiber and high in sugars. Low-fiber diet is believed to cause many health problems, including chronic constipation, hiatal hernias, intestinal infections, colon cancer, and digestion problems. High sugar diets are believed to be the leading cause of adult onset diabetes as well as obesity. These problems are almost entirely absent in "hunting and gathering" cultures that eat much like our ancestors ate.

Like a car, the human body needs many things to run well. The engine in the car needs to have clean oil, it lubricates the engine and allows it to use fuel more efficiently. In the human body, water does much the same thing. Adequate water intake (hydration) is vital for the human body to use its fuel. For all useful purposes, hydration specifically refers to drinking water and no other liquid. Other liquids contain impurities that can interfere with water intake, they can also be consumed, but drinking water alone is vital. A good rule of thumb in water consumption is to have 1 cup of water per 15 lbs of body weight. The water intake should also be spread throughout the day, and is easy to attain if you drink a glass or two of water with every meal.

Nutrition and sports
Nutrition is very important for improving sports performance. Contrary to popular belief, athletes need only slightly more protein than an average person. These needs are easily met by a balanced diet, and the recommended daily servings are generous enough to meet these needs. Additional protein intake is broken-down to be used as energy or stored as fat. Excess protein consumption can lead to acidification of the blood and kidney problems and should be avoided.


 * Aerobic and anaerobic exercises: Endurance, strength and sprint athletes have different needs. Endurance athletes may require an increased caloric intake.


 * Hydration: Maintaining hydration during periods of physical exertion is key to good performance. While drinking too much water during activities can lead to physical discomfort, dehydration hinders an athlete’s ability. It is recommended that an athlete drink about 400-600mL 2-3 hours before activity, during exercise he or she should drink 150-350mL every 15 to 20 minutes and after exercise that he or she replace sweat loss by drinking 450-675 mL for every .5 Kg body weight loss during activity. Studies have shown that an athlete that drinks before they feel thirsty stays cooler and performs better than one who drinks on thirst cues. Sports drinks are not necessary unless endurance-type sports are performed.

The main fuel used by the body during exercise is carbohydrates, which is stored in muscle as glycogen- a form of sugar. During exercise, muscle glycogen reserves can be used up, especially when activities last longer than 90 min. When glycogen is not present in muscles, the muscle cells perform anaerobic respiration producing lactic acid, which is responsible for fatigue and burning sensation, and post exercise stiffness in muscles. Because the amount of glycogen stored in the body is limited, it is important for athletes to replace glycogen by consuming a diet high in carbohydrates. Meeting energy needs can help improve performance during the sport, as well as improve overall strength and endurance.


 * Recovery Period: Meeting energy needs is a top priority for any athlete. Studies have shown that consuming carbohydrates in the period of 30 minutes immediately after termination of the activity improves and speeds up recovery period.

Eating Disorders
Malnutrition Malnutrition is a state in which body functions or development suffers due to inadequate or unbalanced food intake. A malnourished person may suffer from starvation or undernutrition which is when an individual lack's food and thus does not obtain sufficient nutrients or energy to sustain proper growth, body functioning, and development.

Starvation is a severe reduction in vitamins, nutrients, and energy intake, and is the most extreme form of malnutrition. In humans, prolonged starvation (in excess of 1-2 months) causes permanent organ damage and will eventually result in death.

According to the Food and Agriculture Organization of the United Nation, more than 25,000 people die of starvation every day, more than 800 million people are chronically undernourished. On average, every five seconds a child dies from starvation.

Malnutrition is an imbalanced nutrient and or energy intake, regardless of of appearance one can be malnutrition on the fact that they over eat but the food they are consuming is lacking vitamins and minerals needed.

Marasmus is malnutrition caused by a lack of energy referring to Kcalorie intake, this kind of malnutrition the appearance is that of skin and bone.

Kwashiorkor is malnutrition caused by lack of protein, hence, in this kind of malnutrition appearance is a swollen big belly due to inadequate albumin production in the liver, albumin is a protein.

Symptoms

Starved individuals lose substantial fat and muscle mass as the body breaks down these tissues for energy. Catabolysis is the process (medical condition) of a body breaking down the muscles and other tissues in a body in order to keep vital processes such as nervous system and heart muscle working. Catabolysis will not begin until there are no usable sources of energy coming into the body. Catabolysis will break down muscle tissue before it breaks down fat.

Vitamin deficiency is common, often resulting in anemia, beriberi, pellagra, and scurvy. These diseases collectively may cause diarrhea, skin rashes, edema, and heart failure. Individuals are often irritable,fatigue, and lethargic as a result.

Effects Physical


 * Decreased resting metabolic rate (RMR)
 * Drop in sex hormones
 * Decreased sexual interest
 * Amenorrhoea (no menses)
 * Lanugo (growth of insulating hair)
 * Bone loss
 * Constipation and gastrointestinal upset
 * Sleep disorder
 * Muscle weakness
 * Hypothermia
 * Loss of lean body mass
 * Changes in brain chemistry regulating appetite and food cravings

Behavioral
 * Preoccupation with food - collecting recipes
 * Unusual eating habits
 * Increased consumption of fluids
 * Increased use of spices
 * Loss of the body's natural mechanisms for regulating hunger and fullness
 * Less pickiness about tastes
 * Binge eating

Cognitive
 * Decreased concentration
 * Poor judgment
 * Apathy

Emotional and social
 * Depression
 * Anxiety
 * Sandy behavior
 * Lability (constantly changing moods)
 * Psychotic episodes
 * Personality changes
 * Social withdrawal

Treatment

Starvation is usually treated by slowly increasing food intake until no nutrient deficiencies remain. By this time, the diet of a recovering individual should consist of 5,000 calories and twice the Recommended Dietary Allowance of nutrients. Starvation is a result of malnutrition.

Protein Deficiency There are many people that are undernourished and take in too little protein. Adults may suffer from weight loss, weakness, impaired immunity, and other symptoms. This lack of protein can be divesting to infants and children. Chronic protein deficiency in children can lead to Kwashiorkor. The results is a swollen abdomen due to edema (fluid retention) because there are too few proteins in the child's blood plasma. This imbalance causes water to leave the bloodstream and collect in tissue spaces. Affected children are sickly and susceptible to infection. Impaired brain development often leads to permanent mental retardation.

Marasmus We have all seen the gruesome photographs of skeletal children in drought-ridden African countries or elsewhere. These children are affected with Marasmus which affect young children who lack protein and food calories. It is very common in bottle-fed infants from poor families where the parents try to stretch out their supply by watering down the formula and robbing it of most of its nutrients, giving the child mostly water. Symptoms include weight loss, muscle wasting, and retarded growth and mental development. Some effects of Marasmus and Kwashiorkor can be reversed if the child's diet is improved before the damage is too severe. However the affected child will likely function at abnormally low levels both physiologically and intellectually.

Obesity Obesity In Morgan Spurlock's film Super Size Me he discusses how obesity became an epidemic in the United States. Morgan Spurlock states that 400,000 people will die this year as a result of obesity and that obesity has become the second leading cause of preventable death in the United States behind smoking. Super Size Me points out that 25% of our population will eat at least one meal from a fast food restaurant in any given day. While his views are viewed as controversial by some, there is no denying that fast food has significantly contributed to the obesity crisis that the United States now faces.

Body Mass Index(BMI) is a major guideline that doctors and dietitians both use to determined obesity. In its simplest form it involves dividing the subject's weight in kilograms by the square of his/her height in meters (BMI = kg / m2) and then comparing it to a chart of numbers that correspond to the person’s gender. This approach can show inaccuracies in that it does not take into account the persons age, muscle mass or other unique criteria that a trained professional can use to define an obese person.

The current definitions commonly in use establish the following values, agreed in 1997 and published in 2003:


 * A BMI less than 18.5 is underweight
 * A BMI of 18.5 - 24.9 is normal weight
 * A BMI of 25.0 - 29.9 is overweight
 * A BMI of 30.0 - 39.9 is obese
 * A BMI of 40.0 or higher is severely (or morbidly) obese



Causative factors

When food energy intake exceeds energy expenditure, fat cells (and to a lesser extent muscle and liver cells) throughout the body take in the energy and store it as fat. In its simplest conception, therefore, obesity is only made possible when the lifetime energy intake exceeds lifetime energy expenditure by more than it does for individuals of "normal weight".

In all individuals, the excess energy utilized to generate fat reserves is minute relative to the total number of calories consumed. This means that very fine perturbations in the energy balance can lead to large fluctuations in weight over time. To illustrate, an obese 40 year old who carries 100 lb of adipose tissue has only consumed about 25 more calories per day than he has burned on average - or the equivalent of an apple every three days. In comparison a very lean 40-year-old who carries only 15 lb of body fat will have exceeded his daily energy expenditure by about four calories a day - the equivalent of an apple every 18 days.

Some causes of obesity are bases on genetics. This principle is common with some native American cultures. There is a starvation gene in them that is not seen usually in European descendants. This is were the body has the ability be super efficient at metabolizing food. This causes a the body to increase the stores of glycogen and adipose tissue. In early hunter and gatherer days this was a very desirable feature in that it was easier to go without food for long periods of time. The gene is not as desirable in today’s world because of the super efficient way food is produced and delivered. Allowing the person have a readily stable supply of food without the need to expend a lot of energy to obtain it. Several lines of evidence indicate lifestyle-induced hyperinsulinemia and reduced insulin function (i.e. insulin resistance) as a decisive factor in many disease states. For example, hyperinsulinemia and insulin resistance are strongly linked to chronic inflammation, which in turn is strongly linked to a variety of adverse developments such as arterial microinjuries and clot formation (i.e. heart disease) and exaggerated cell division (i.e. cancer). Hyperinsulinemia and insulin resistance (the so-called metabolic syndrome) are characterized by a combination of abdominal obesity, elevated blood sugar, elevated blood pressure, elevated blood triglycerides, and reduced HDL cholesterol. The negative impact of hyperinsulinemia on prostaglandin PGE1/PGE2 balance may be significant.

The state of obesity clearly contributes to insulin resistance, which in turn can cause type 2 diabetes. Virtually all obese and most type 2 diabetic individuals have marked insulin resistance. Although the association between obesity and insulin resistance is clear, the exact (likely multifarious) causes of insulin resistance remain less clear. Importantly, it has been demonstrated that appropriate exercise, more regular food intake and reducing glycemic load (see below) all can reverse insulin resistance in obese individuals (and thereby lower blood sugar levels in those who have type 2 diabetes).

Obesity can unfavorably alter hormonal and metabolic status via resistance to the hormone leptin, and a vicious cycle may occur in which insulin/leptin resistance and obesity aggravate one another. The vicious cycle is putatively fuelled by continuously high insulin/leptin stimulation and fat storage, as a result of high intake of strongly insulin/leptin stimulating foods and energy. Both insulin and leptin normally function as satiety signals to the hypothalamus in the brain; however, insulin/leptin resistance may reduce this signal and therefore allow continued overfeeding despite large body fat stores. In addition, reduced leptin signaling to the brain may reduce leptin's normal effect to maintain an appropriately high metabolic rate.

There is debate about how and to what extent different dietary factors -- e.g. intake of processed carbohydrates, total protein, fat, and carbohydrate intake, intake of saturated and trans fatty acids, and low intake of vitamins/minerals -- contribute to the development of insulin- and leptin resistance. In any case, analogous to the way modern man-made pollution may potentially overwhelm the environment's ability to maintain 'homeostasis', the recent explosive introduction of high Glycemic Index- and processed foods into the human diet may potentially overwhelm the body's ability to maintain homeostasis and health (as evidenced by the metabolic syndrome epidemic).

Antioxidants are another recent discovery. As cellular metabolism/energy production requires oxygen, potentially damaging (e.g. mutation causing) compounds known as radical oxygen species or free radicals form as a result. For normal cellular maintenance, growth, and division, these free radicals must be sufficiently neutralized by antioxidant compounds, some produced by the body with adequate precursors (glutathione, Vitamin C in most animals) and those that the body cannot produce may only be obtained through the diet through direct sources (Vitamin C in humans, Vitamin A, Vitamin K) or produced by the body from other compounds (Beta-carotene converted to Vitamin A by the body, Vitamin D synthesized from cholesterol by sunlight). Different antioxidants are now known to function in a cooperative network, e.g. vitamin C can reactivate free radical-containing glutathione or vitamin E by accepting the free radical itself, and so on. Some antioxidants are more effective than others at neutralizing different free radicals. Some cannot neutralize certain free radicals. Some cannot be present in certain areas of free radical development (Vitamin A is fat-soluble and protects fat areas, Vitamin C is water soluble and protects those areas). When interacting with a free radical, some antioxidants produce a different free radical compound that is less dangerous or more dangerous than the previous compound. Having a variety of antioxidants allows any byproducts to be safely dealt with by more efficient antioxidants in neutralizing a free radical's butterfly effect.

Side Effects of Obesity Sexual dysfunction 

In Morgan Spurlock's film Super Size Me one of the affects of his McDonalds diet was Sexual Dysfunction. In this section we will examine a University Of Naples study and what physiological effects obesity has on the reproductive system.

One factor that is thought to lead to sexual dysfunction is low self-esteem about body image. While the physiological effects that one’s self image does have an impact on sexual performance there is also evidence that erectile dysfunction may be physiologically related to obesity. According to emaxhealth.com, experts speculate that 90 percent of erectile dysfunction is physical in origin, not psychological. Emaxhealth.com sites a two-year study conducted at the Second University of Naples, Italy.

In the University of Naples study 55 men were closely supervised by medical professionals and counseled on diet, fitness and personal behavioral. This group met with a personal trainer at regular intervals and every member of this group lost weight. The control group of 55 men in the University of Napals study just got general information about exercise and healthy dietary choices during visits every other month during the two-year study period. The weight loss results in this group were not statistically significant. The first group that lost weight experienced various health and sexual function improvements. In fact, by the time they'd achieved a weight loss of just 10 percent, erectile dysfunction was completely alleviated for one out of three men in that group. In the second group only three of the men had recovered normal erectile function.  Liver Failure  One of the most surprising results of Morgan Spurlock's McDiet experiment was the damage that was done to his liver. In his documentary he went to three different doctors who were all amazed that the liver could be so negatively affected from a short term fast food binge. The liver is amazing in that it can regenerate itself, however obesity can put a major strain on this vital organ.

A liver condition that many obese people experience is non alcoholic fatty liver disease. Non alcoholic fatty liver disease can appear in the form of a fatty liver (accumulation of fat in the liver, also known as steatosis), to non alcoholic steatohepatitis (NASH, fat in the liver causing liver inflammation), to cirrhosis (irreversible, advanced scarring of the liver as a result of chronic inflammation of the liver). All of the stages of non alcoholic fatty liver disease are now believed to be due to insulin resistance, a condition closely associated with obesity.

Heart Disease 

Therapy

The mainstay of treatment for obesity is an energy-limited diet and increased exercise. In studies, diet and exercise programs have consistently produced an average weight loss of approximately 8% of total body mass on average (excluding study drop-outs). While not all dieters will be satisfied with this outcome, studies have shown that a loss of as little as 5% of body mass can create enormous health benefits.

A more intractable therapeutic problem appears to be weight loss maintenance. Of dieters who manage to lose 10% or more of their body mass in studies, 80-95% will regain that weight within two to five years. It appears that the homeostatic mechanisms regulating body weight are very robust (see leptin, for example), and vigorously defend against weight loss. Much important research is now being devoted to determining what factors can improve the currently dismal weight loss maintenance rates.

Recent scientific research has cast some doubt over whether or not dieting actually improves health, with some studies indicating that dieting may in fact be more detrimental than remaining overweight.

In a clinical practice guideline by the American College of Physicians the following three recommendations were made for obese people to achieve weight loss.

Counseling on diet and exercise People with a BMI of over 30 should be counseled on diet, exercise and other relevant behavioral interventions, and set a realistic goal for weight loss. If these goals are not achieved, Pharmacotherapy and bariatric surgery may be an option. Pharmacotherapy The patient needs to be informed of the possibility of side-effects and the unavailability of long-term safety and efficacy data. Drug therapy may consist of sibutramine, orlistat, phentermine, diethylpropion, fluoxetine, and bupropion. For more severe cases of obesity, stronger drugs such as amphetamine and methamphetamine may be used on a selective basis. Evidence is not sufficient to recommend sertraline, topiramate, or zonisamide. In patients with BMI > 40 who fail to achieve their weight loss goals (with or without medication) and who develop obesity-related complications, referral for bariatric surgery may be indicated. Medication most commonly prescribed for diet/exercise-resistant obesity is orlistat (Xenical®, which reduces intestinal fat absorption by inhibiting pancreatic lipase) and sibutramine (Reductil®, Meridia®, an anorectic). In the presence of diabetes mellitus, there is evidence that the anti-diabetic drug metformin (Glucophage®) can assist in weight loss — rather than sulfonylurea derivatives and insulin, which often lead to further weight gain. The thiazolidinediones (rosiglitazone or pioglitazone) can cause slight weight gain, but decrease the "pathologic" form of abdominal fat, and are therefore often used in obese diabetics. Bariatric surgery Bariatric surgery entails modifying the stomach and or intestines to help the patient with extreme obesity. Those requiring bariatric surgery should be referred to high-volume referral centers, as the evidence suggests that surgeons who frequently perform these procedures have fewer complications. Increasingly, bariatric surgery is being used to combat obesity. The most common weight loss surgery in Europe and Australia is the use of a adjustable gastric band where a silicone ring is placed around the top of the stomach to help restrict the amount of food eaten in a sitting. This surgery has been FDA approved in the United States since 2001 but has been being used in other parts of the world since the early 1990s. It is considered the safest and least invasive of the available weight loss surgeries such as Roux-en-Y gastric bypass surgery (RNY), biliopancreatic diversion, and stomach stapling (also known as vertical banded gastroplasty, VBG). Unlike those more invasive techniques the band surgery does not cut into or reroute the digestive tract and is completely reversible. Removing the implant returns the stomach to its pre-surgical norm. All of these surgeries can be done laparoscopically. The more invasive of the surgeries usually bypass or remove some portion of the patient's intestines which causes malabsorption and dumping. All of these surgeries come with risk to the patient. For instance a recent study by the U.S. Department of Health and Human Service showed a 40% complication rate within 180 days of bariatric surgery. Moreover these surgeries do not guarantee either successful weight loss or reduced morbidity and mortality. Patients are also required to make lifelong changes to their diet if they are to keep the lost weight off in the long term. Therefore, as with any major surgery, patients need to carefully evaluate the long term ramifications of their choice.

In Morgan Spurlock's Super Size Me a section of the movie covered the gastric bypass surgery of an obese man. The surgery appeared to go well and nine months later the man had been able to loose 100 lbs. Bulimia Nervosa

Bulimia nervosa, more commonly known as bulimia, is an eating disorder. It is a psychological condition in which the subject engages in recurrent binge eating followed by an intentional purging. This purging is done in order to compensate for the excessive intake of the food and to prevent weight gain. Purging typically takes the form of:

vomiting inappropriate use of laxatives, enemas, diuretics or other medication excessive exercising fasting DSM-IV criteria The following six criteria should be met for a patient to be diagnosed with bulimia1 2:

The patient feels incapable of controlling the urge to binge, even during the binge itself, and consumes a larger amount of food than a person would normally consume at one sitting. The patient purges him or herself of the recent intake, resorting to vomiting, laxatives, diuretics, exercising, etc. The patient engages in such behavior at least twice per week for three months. The patient is focused upon body image and desperate desire to appear thin. The patient does not meet the diagnostic criteria for anorexia nervosa. (Some anorexics may demonstrate bulimic behaviors in their illness: binge-eating and purging themselves of food on a regular or infrequent basis at certain times during the course of their disease. Alternatively, some individuals might switch from having anorexia to having bulimia. The mortality rate for anorexics who practice bulimic behaviors is twice that of anorexics who do not. The patient is of normal weight or overweight. Please note that, in general, diagnostic criteria are considered a guide. A legitimate clinical diagnosis can be made when the majority of the criteria are met.

edit History of bulimia nervosa Bulimia nervosa was first described by Professor Gerald Russell in 1979 whilst he worked at the Royal Free Hospital, London. Bulimia nervosa has been recognized as an autonomous eating disorder by the American Psychiatric Association since 1980. The word “bulimia” is Latin, getting its roots from the Greek word “bulimia” which directly translates to mean “extreme hunger”.

Causes Bulimia is often less about food, and more to do with deep psychological issues and profound feelings of lack of control. Binge/purge episodes can be severe, sometimes involving rapid and out of control feeding that can stop when the sufferers "are interrupted by another person or when their stomach hurts from over-extension. This cycle may be repeated several times a week or, in serious cases, several times a day." Sufferers can often "use the destructive eating pattern to gain control over their lives".

Genetic factors Research done in 2003, shows a link to the development of bulimia nervosa with an area on the 10p chromosome. This evidence further supports the belief that the susceptibility of developing an eating disorder (specifically bulimia) is strongly linked to genetic components 8. Familial links include a history of obesity, substance abuse, and depressive disorder. Twin studies also strongly support this genetic factor. While both genetics and unique environments contributed to the development of the disorder, twin studies indicate a slightly stronger effect from the genetic predisposition than from environmental circumstances. Significant rates of sexual assault and violence also indicate a possible correlation between victimization and the development of bulimia. Chemically, low levels of serotonin contribute to the continuation of the bulimic cycle; whether it is contributing to or arising from the nutritional deficiency and vomiting is still undetermined. The protein leptin decreases hunger levels in a person, and is often blocked in patients with bulimia, causing abnormal levels of hunger. Due to the binging and purging cycle the stomach is frequently stretched to an enlarged state, and over the progression of time, becomes permanently enlarged, making it necessary for more food to be in the person’s stomach to reach a level of satisfaction. This is a primary cause of the need for a bulimic to gradually increase the caloric size of their binges, as the original quantities no longer satisfy their enlarged stomach.

Environmental factors Rates of bulimia are much more prevalent in western civilizations, to the point that the disorder is almost non-existent in eastern cultures. As western civilization is becoming a more prominent figure in other cultures, through movies and television primarily, we are seeing a dramatic increase in the incidence of eating disorders in these cultures. The disorder is also much more prevalent in the Caucasian race, though as media influences have become stronger, the disorder is becoming a rising problem in the African American and Hispanic communities. Women are also 90% of patients who suffer from this disorder. Females involved in activities that put an extreme emphasis on thinness and body type (such as gymnastics, dance and cheerleading) are at the greatest risk for the development of eating disorders.

Patterns of bulimic cycles The frequency of bulimic cycles will vary from person to person. Some will suffer from an episode every few months while others who are more severely ill may binge and purge several times a day. Some people may vomit automatically after they have eaten any food. Others will eat socially but may be bulimic in private. Some people do not regard their illness as a problem, while others despise and fear the vicious and uncontrollable cycle they are in.

Subtypes of bulimia The specific subtypes differ in the way the bulimic relieves him or herself of the binge. Purging type - The purging type uses self-induced vomiting, laxatives, diuretics, enemas, or ipecac, as a mean of rapidly extricating the contents for their body. This type generally is more commonly found, and can use one or more of the above methods on a regular basis 12.

Non-Purging Type - This type of bulimic is very rarely found (only approximately 6%-8%), as it is a less effective means of ridding the body of such a large number of calories. This type of bulimic engages in excessive exercise or fasting following a binge in order to counteract the large amount of calories previously ingested. This is frequently observed in purging type bulimics as well, however this method is not their primary form of weight control following a binge 13. edit Consequences of bulimia nervosa Malnutrition Dehydration Electrolyte imbalance Hyponatremia Vitamin and mineral deficiencies Teeth erosion and cavities, gum disease Sialadenosis (salivary gland swelling) Potential for gastric rupture during periods of bingeing Esophageal reflux Irritation, inflammation, and possible rupture of the esophagus Laxative dependence Peptic ulcers and pancreatitis Emetic toxicity due to ipecac abuse Swelling of the face and cheeks Callused or bruised fingers Dry or brittle skin, hair, and nails, or hair loss Lanugo Edema Muscle atrophy Decreased/increased bowel activity Digestive problems that may be triggered, including Celiac, Crohn's Disease Low blood pressure, hypotension Orthostatic hypotension High blood pressure, hypertension Iron deficiency, anemia Hormonal imbalances A case of the television show "Untold Stories of The ER", airing on TLC in Canada, a young girl with a severe case of Bulimia nervosa managed to get her gag reflex suppressed, resulting in her using forks to induce vomiting, which ultimately got stuck very deep in her esophagus, and was almost in her stomach. She is lucky, as she escaped with no damage, but her parents found out and she had to be treated accordingly. Hyperactivity Depression Insomnia Amenorrhea Infertility Polycystic Ovary Syndrome High risk pregnancy, miscarriage, still-born babies Diabetes Elevated blood sugar or hyperglycemia Ketoacidosis Osteoporosis Arthritis Weakness and fatigue Chronic Fatigue Syndrome Cancer of the throat or voice box Liver failure Kidney infection and failure Heart failure, heart arrhythmia, angina Seizure Paralysis Potentially death caused by heart attack or heart failure; lung collapse; internal bleeding, stroke, kidney failure, liver failure; pancreatitis, gastric rupture, perforated ulcer, depression and suicide. edit Diagnosis As mentioned earlier, all six of the criteria listed in the DSM are required for a classic diagnosis of bulimia nervosa. However, these symptoms are often difficult to spot, especially since, unlike anorexia nervosa, in order to be classified as bulimic the person must be of normal or higher weight. Likewise, the person is less likely to drop a significant amount of weight on a continual basis as does the anorectic, making the physical symptoms less noticeable, despite the fact that internal bodily functions are suffering. Because this disorder carries a great deal of shame, the bulimic will desperately try to hide their symptoms from family and friends. This disorder is more likely to span over a lifetime unnoticed, causing a great deal of isolation and stress for the suffering individual. Despite the frequent lack of obvious physical symptoms, bulimia nervosa has proven to be fatal, as malnutrition takes a serious toll on every organ in your body. If any of the symptoms above are noticed one should consult with a doctor or psychologist for further assistance.

Anorexia Nervosa Anorexia nervosa is an illness that usually occurs in adolescent girls, but it can also occur in adolescent boys, and adult women and men. People with anorexia are obsessed with being thin. They lose a lot of weight and are terrified of gaining weight. The believe they need to lose weight even though they are very thin or emaciated. Anorexia isn't just a problem with food or weight. It's an attempt to use food and weight to deal with emotional problems. What is the difference between anorexia and bulimia? People with anorexia starve themselves. People with bulimia eat huge amounts of food, but they throw up soon after eating, or take laxatives or diuretics (water pills) to keep from gaining weight. People with bulimia don't usually lose as much weight as people with anorexia.

Why do people get anorexia? The reason some people get anorexia isn't known. People with anorexia may believe they would be happier and more successful if they were thin. They want everything in their lives to be perfect. People who have this disorder are usually good students. They are involved in many school and community activities. They blame themselves if they don't get perfect grades, or if other things in life are not perfect and use anorexia as a way to deal or gain control. Chronic and excessively forceful holding of the belly tightly flat often accomompanies this disorder; it is part of being thin. This inhibits abdominal breathing, causing increased chest breathing - which is more ineffecient and stress inducing. If the chest is also held rigidly lifted or otherwise held immobile (often due to issues related to self-image and the developing breasts) breathing becomes problematic, as likewise digestion of food (including normal appetite), which depends on an activated parasympathetic nervous system (which includes relaxed effortless breathing). Ineffecient or labored breathing is often associated with sympathetic activation. What is the treatment for anorexia? Treatment of anorexia is difficult, because people with anorexia believe there is little or nothing wrong with their weight, they may know they are too thin but believe it is okay for them. Patients in the early stages of anorexia (less than 6 months or with just a small amount of weight loss) may be successfully treated without having to be admitted to the hospital. But for successful treatment, patients must want to change and must have family and friends to help them. People with more serious anorexia need care in the hospital, usually in a special unit for people with anorexia and bulimia. Treatment involves more than changing the person's eating habits. Anorexic patients often need counseling for a year or more so they can work on changing the feelings that are causing their eating problems. These feelings may be about their weight, their family problems or their problems with self-esteem. Some anorexic patients are helped by taking medicine that makes them feel less depressed or better in their daily lives. These medicines are prescribed by a doctor and are used along with counseling.

Weight loss
Low Carb Diets Programs such as the South Beach, Atkins and Zone diets, are claimed to work because they reduce insulin levels, which in turn causes the body to burn its fat for energy. As a process, these kinds of diets have been in and out of fashion since the Banting diet appeared in the 19th century. But long before modern scientific invention, anecdotal and holistic prescriptions, containing passages about limiting certain foods, including foods of mostly carbohydrates, have appeared throughout history. Although strong evidence suggests, and general agreement claims, that low carb diets can help achieve weight loss, some have been controversial among nutritionists, and their relative safety has been challenged.

Arguments for low-carbohydrate diets The evolutionary argument Some advocates of low carb diets argue that the Paleolithic diet did not include grains, starches, and refined sugar, and that the human body has not evolved significantly since the time of the Neolithic Revolution, implying that their consumption should still be avoided today and causes undesired and largely unknown effects. Specifically, it is argued that they cause the body to produce excess amounts of the hormone insulin, which tells the body to store rather than burn fat, hence causing obesity and its complications (heart disease, cancer, Type 2 diabetes). They claim that humans evolved to eat a diet which consisted mainly of meat and that the current "epidemic" of obesity is due to the popular assumption, reinforced by the food industry and the new field of dietary medicine, that the low-fat approach is healthier.

Supporters claim the exclusive focus on reducing fat is oversimplified, and that low-fat diets are not automatically healthy ones. They claim that the western world is not suffering from a collective failure of will to exercise, but has been encouraged to eat more carbohydrates, which in turn stimulate appetite and more eating.

The recent rise in western obesity rates has coincided with a widespread belief in low-fat, high-carbohydrate as a healthy way of eating. By contrast traditional, high-fat French cooking has led to a much lower incidence of obesity, morbid obesity and chronic heart disease than the high-sugar American diet, despite overall energy intake and exercise levels being the same.

Favorable studies Advocates point to scientific trials demonstrating the efficacy and safety of low carb diets. Several independent clinical trials have shown that low carb diets can be successfully used to lose weight. These trials found that, in the short term, risk factors for heart disease and Type 2 diabetes — such as blood serum cholesterol and insulin levels — tended to improve in spite of increased consumption of saturated fat and cholesterol. The trials were of short duration, and were not able to assess the long-term health effects of the diet.

A study conducted in 1965 at the Oakland (California) Naval Hospital used a diet of 1000 calories per day, high in fat and limiting carbohydrates to 10 grams (40 calories) daily. Over a ten-day period, subjects on this diet lost more body fat than did a group who fasted completely. (Benoit et. al. 1965). Some advocates of low-carbohydrate diets have termed this the metabolic advantage of such diets.

Major research can be found at http://www.nutritionj.com/content/3/1/9

Arguments against low-carbohydrate diets In 2004, a Canadian court ruled that foods sold in Canada could not be marketed with reduced or eliminated carbohydrate content as a selling point because carbohydrates were determined not to be a health risk, and that existing "low carb" and "no carb" packaging would have to be phased out by 2006. This is not an argument against low carb diets, but is instead marketing regulatory action intended to avoid abuses.

Side effects Critics contend that low carbohydrate diets are not without harmful side effects. The lowered intake of dietary fiber that often accompanies dramatically reduced carbohydrate intake can result in constipation if not supplemented. For example, this has been a criticism of the Induction stage of the Atkins diet (note that today the Atkins diet is more clear about recommending a fiber supplement during Induction).

Replacement of calories from carbohydrates with meat may result in high consumption of saturated fat and cholesterol, which many authorities believe will increase the risk of heart disease. Moreover, it has been hypothesized that the kidneys can become overworked and that a related change in blood acidity can lead to bone loss, but trials testing the hypothesis have found no evidence of kidney damage or loss of bone.

Cutting out carbohydrates means missing out on vital nutrients from healthy carbohydrate foods which should be part of any well-balanced diet, especially those from fruits, vegetables and whole grains. If you’re considering a low-carb diet for weight loss, remember to count your calories and make sure you get enough nutrients