Nutrition and Metabolism

Nutrition (also called nourishment or aliment) is the provision, to cells and organisms, of the materials necessary (in the form of food) to support life. Many common health problems can be prevented or alleviated with a healthy diet.

The diet of an organism is what it eats, which is largely determined by the perceived palatability of foods. Dietitians are health professionals who specialize in human nutrition, meal planning, economics, and preparation. They are trained to provide safe, evidence-based dietary advice and management to individuals (in health and disease), as well as to institutions. Clinical nutritionists are health professionals who focus more specifically on the role of nutrition in chronic disease, including possible prevention or remediation by addressing nutritional deficiencies before resorting to drugs. While government regulation of the use of this professional title is less universal than for "dietician", the field is supported by many high-level academic programs, up to and including the Doctoral level, and has its own voluntary certification board

Anorexia

It is an eating disorder that leads people to lose more weight than is considered healthy for their age and height.

People with this disorder may have an intense fear of gaining weight, even when they are underweight. You may make dieting or exercising excessively or using other methods to lose weight.

causes

No one knows the exact causes of anorexia nervosa. Many factors probably are involved. Genes and hormones may play a role. Social attitudes that promote very slim body types may also contribute.

It is not believed that the conflicts within the family contribute to this or other eating disorders.

Risk factors predisposing to anorexia include:

     Be more concerned or pay more attention to weight and shape
     Having an anxiety disorder in childhood
     Having a negative self-image
     Have food problems during infancy or early childhood
     Have certain ideas about cultural and social health and beauty
     Trying to be a perfectionist or too focused on rules

Anorexia usually begins during the teenage years or early adulthood and is more common in women, but can also be seen in males. The disorder is seen mainly in Caucasian women, high achievement and who have family or personality oriented towards achieving goals.

Anorexia usually begins during the teenage years or early adulthood and is more common in women, but can also be seen in males. The disorder is seen mainly in Caucasian women, high achievement and who have family or personality oriented towards achieving goals.
symptoms

To be diagnosed with anorexia, a person must:

     Having an intense fear of gaining weight or becoming fat, even when they are underweight.
     Refusal to maintain weight in what is considered normal for their age and height (15% or more below normal weight).
     Having a body image that is very distorted, be very focused on body weight or shape, and refused to admit the gravity of the weight loss.
     Have not had your period for three or more cycles (in women).

People with anorexia may severely limit the amount of food they eat, or eat and then vomit. Other behaviors include:

     Cut food into small pieces or move them around the plate instead of eating them.
     Exercise at all times, even in bad weather, are injured or are too busy.
     Go to the bathroom immediately after meals.
     Refusing to eat around other people.
     Using pills that make urination (diuretics), have a bowel movement (enemas or laxatives) or decrease your appetite (diet pills)

Bulimia

It is an eating disorder that leads people to lose more weight than is considered healthy for their age and height.

People with this disorder may have an intense fear of gaining weight, even when they are underweight. You may make dieting or exercising excessively or using other methods to lose weight.

  causes

Many more women than men have bulimia, and the disorder is more common in adolescent girls and young women. The affected person is usually aware that her eating pattern is abnormal and may experience fear or guilt with episodes of binge and purge.

It is unknown the exact cause of bulimia, but genetic, psychological trauma, family, social or cultural factors may play a role. Bulimia is likely due to more than one factor.
symptoms

In bulimia, there may be episodes of overeating at a frequency of several times a day for many months.

People with bulimia typically eat large quantities of high calorie foods, usually in secret. The person often feels a lack of control over their eating during these episodes.

These episodes of excessive ingestion of foods cause a feeling of self-rejection, which leads to so-called purge to prevent weight gain. Purging may include:

     Induce vomiting.
     Excessive exercise.
     Use of laxatives, enemas or diuretics.

The purge often produces a feeling of relief.

People with bulimia are often normal weight, but they can see themselves overweight. Because the weight is often normal, others may not notice this eating disorder.

Diet

Diet food (or dietetic food) refers to any food or drink whose recipe has been altered in some way to make it part of a body modification diet. Although the usual intention is weight loss and change in body type, sometimes the intention is to aid in gaining weight or muscle as in bodybuilding supplements.

In addition to diet other words or phrases are used to identify and describe these foods including light or lite, lean, no calorie, low calorie, low fat, no fat, fat free, no sugar, sugar free, and zero calorie. In some areas use of these terms may be regulated by law. For example in the U.S. a product labeled low fat must not contain more than 3 grams of fat per serving; and to be labeled fat free it must contain less than 0.5 grams of fat per serving.


The process of making a diet version of a food usually requires finding an acceptable low-food-energy substitute for some high-food-energy ingredient. This can be as simple as replacing some or all of the food's sugar with a sugar substitute as is common with diet soft drinks such as Coca-Cola (for example Diet Coke). In some snacks, the food may be baked instead of fried thus reducing the food energy. In other cases, low-fat ingredients may be used as replacements.

In whole grain foods, the higher fiber content effectively displaces some of the starch component of the flour. Since certain fibers have no food energy, this results in a modest energy reduction. Another technique relies on the intentional addition of other reduced-food-energy ingredients, such as resistant starch or dietary fiber, to replace part of the flour and achieve a more significant energy reduction.

In diet foods which replace the sugar with lower-food-energy substitutes, there is some controversy based around the possibility that the sugar substitutes used to replace sugar are themselves harmful. Even if this question is satisfactorily resolved (which remains unlikely at this time, the question still remains as to whether the benefits of food energy reduction would outweigh the potential loss.

In many low-fat and fat-free foods the fat is replaced with sugar, flour, or other full-food-energy ingredients, and the reduction in food energy value is small, if any.  Furthermore, an excess of digestible sugar (as well as an excess of any macronutrient) is stored as fat