Diet, Weight Loss and Nutrition Resources

Here you will find information relating to popular and medical diet plans disciplines, and weight loss suppliments. To navigate, please see the links in the left column of this page.

Dieting is the practice or habit of eating (and drinking) in a regulated fashion, usually with the aim of losing weight. It is also used in some cases to gain weight or to regulate the amount(s) of certain nutrients entering the body.

Scientific principles surrounding dieting

Successful weight loss diet is all about energy in versus energy out. If a person takes in fewer calories than he or she expends over a period of time, the person may burn fat and subsequently lose weight.

Diets affect the energy in component of the energy balance by limiting or altering the distribution of foods. Techniques that affect the appetite can limit energy intake by affecting the desire to overeat. This can be attempted by focusing on foods that are filling, through the use of certain appetite-suppressing drugs, or through activities such as mild exercise, that affect appetite. Other techniques address habitual or emotional eating.

Affecting the energy out component is the focus of fitness and exercise programs. These might also be included in a comprehensive "diet."

Dieting in order to lose weight does just that -- you lose weight, water, some fat and muscles. Since muscles are denser, you lose a lot of weight, but little in size. Fat is bulkier, so a three pound fat loss can cause a size loss.

To lose a pound of fat, one must create a caloric deficit of approximately 3,500 calories (37,600 kJ per kilogram of fat); therefore, if a person creates a deficit of 500 calories per day, the person will lose approximately 1 pound of fat per week (5,400 kJ per day to lose a kilogram a week).

Muscle-loss during weight-loss can be restricted by regularly lifting weights and by a high protein intake. (It is said that 0.8 to 1.0 g of protein per pound of body weight (1.76 to 2.20 g per kg) per day is sufficient.) A ketogenic diet is often very effective in lowering body-fat levels whilst maintaining or even increasing muscle mass.

Fad diets

Many 'fad' diets become widely popular for a short period of time, only to fade out. Although some fade from popularity due to being ineffective, some merely lose the public's interest. Judging their nutritional merit can be especially difficult given that most diet proponents locate medical professionals to back up their work. Examples of such fads include the grapefruit diet, low-fat diets, and Atkins.

Most fad diets overlook the basic nutritional idea of energy balance discussed in greater detail above. The energy you take in (in the form of calories in food, whether fat, protein, or carbohydrate) must be less than the energy you burn in order to lose weight, so that your body burns fat to make up the energy deficit. If you take in more energy than you burn, your body will tend to store this excess energy as fat.

Atkins encourages controlling carbohydrate intake, and encouraged meats, nuts, unsweetened fruits, berries and green vegetables. This causes rapid weight loss for many people, although it continues to be disputed whether this is due to a metabolic advantage of ketosis, as Atkins claimed. Some of the initial rapid weight loss is due to depletion of glycogen stores in the liver. Glycogen must be associated with several times its weight of water in the body. Low carbohydrate diets have been shown to reduced the fasting levels of triglycerides. Elevated triglycerides are a demonstrated risk factor for heart disease and also account for part of the risk of low density cholesterol due to their associated worse particle size profile. Any successful diet for losing weight will cause some ketosis, since ketones are produced when the body is using fat energy to synthesize glucose (gluconeogenesis) during the long overnight fast (sleep). Elevated levels of fasting triglycerides (TGs) are the product of de novo lipogenesis (synthesis of new fats) from glucose substrate. If the liver was engaged in gluconeogenesis from fat, and synthesizing fat from glucose at the same time, this would be a futile cycle, and a fantastic way to waste energy and lose weight. For most of human history, it has been important to survival to avoid such inefficiency, so the body switches modes to avoid this futile cycle. This explains the dramatic reductions in fasting TGs seen in many low carbohydrate dieters.

Atikins is not strictly a fad diet, since it is an approach that is still quite popular.

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