Side effects

Dieting, especially extreme food-intake reduction and rapid weight loss, can have the following side effects:
Prolonged hunger
Fainting
Reduced sex drive
Fatigue
Irritability
Sinus problems (especially post-nasal drip)
Muscle atrophy
Rashes
Acidosis
Bloodshot eyes
Gallbladder disease
Depression
Subsequent weight gain

Dangers of fasting

Lengthy fasting can be dangerous due to the risk of malnutrition and should be carried out under medical supervision. During fasting or very low calorie diets the reduction of blood glucose, the preferred energy source of the brain, causes the body to metabolize sugars from protein. Most experts believe that a prolonged fast can lead to muscle wasting although some dispute this.

Medications

Certain medications can be prescribed to assist in weight loss. The most recent prescription weight loss medication released is Acomplia manufactured by Sanofi Aventis. Used to treat obesity in persons with a BMI ( body mass index) of 30 or above as well as for smoking cessation treatments, Acomplia is still pending FDA approval for use in the United States of America Other weight loss medications, like amphetamines, are dangerous and are now banned for casual weight loss. Some supplements, including those containing vitamins and minerals, may not be effective for losing weight

Physical exercise

is an important complement to dieting in securing weight loss. Aerobic exercise is also an important part of maintaining normal good health, especially the muscular strength of the heart. To be useful, aerobic exercise requires maintaining a target heart rate of 50 percent above one's resting heart rate for 30 minutes, at least 3 times a week. Brisk walking can accomplish thisAlways consult a physician before beginning any exercise program.
The ability of a few hours a week of exercise to contribute to weight loss can be somewhat overestimated. To illustrate, consider a 100-kilogram man who wants to lose 10 kilograms and assume that he eats just enough to maintain his weight (at rest), so that weight loss can only come from exercise. Those 10 kilograms (22 lb) converted to work are equivalent to about 350 megajoules (84,000 kilocalories). Now assume that his chosen exercise is stairclimbing and that he is 20 percent efficient at converting chemical energy into mechanical work To lose the weight, he must ascend 70 kilometers. A man of normal fitness will be tired after 500 meters of climbing (about 150 flights of stairs), so he needs to exercise every day for 140 days (to reach his target). However, exercise (both aerobic and anaerobic) would increase the Basal Metabolic Rate (BMR) for some time after the workout. This ensures more calorific loss than otherwise estimated.
The minimum safe dietary energy intake (without medical supervision) is 75 percent of that needed to maintain basal metabolism For our hypothetical 100-kilogram man, that minimum is about 5,700 kilojoules (1,300 kilocalories) per day. By combining daily aerobic exercise with a weight-loss diet, he would be able to lose 10 kilograms in half the time (70 days).
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Types of dieting

diet. There are several kinds of diets:
Weight-loss diets restricts the intake of specific foods, or food in general, to reduce body weight. What works to reduce body weight for one person will not necessarily work for another, due to metabolic differences and lifestyle factors. Also, for a variety of reasons, most people find it difficult to maintain significant weight loss over time — among individuals that have lost 15% or more of body weight, only 20% are able to maintain that weight loss for a full year.
Many professional athletes impose weight-gain diets on themselves. American football players may try to "bulk up" through weight-gain diets in order to gain an advantage on the field with a higher mass.

As more cultures scrutinize their diets, many parents consider putting their children on restricted diets that actually do more harm than good. This is extremely harmful to a young child's health because a full and balanced diet (fats, carbohydrates, protein, vitamins, minerals, fiber, etc.) is needed for growth. Research also shows that putting children on diet foods can be harmful. The brain is unable to learn how to correlate taste with nutritional value, which is why such children may consistently overeat later in life despite adequate nutritional intake.
Individuals who are underweight, such as those recovering from anorexia nervosa or starvation, may adopt weight-gain diets which, unlike those of athletes, have the goal of restoring normal levels of body fat, muscle, and stores of essential nutrients. A doctor should be consulted before putting any child on a specialized diet.

Dieting

Dieting In most cases the goal is weight loss in those who are overweight or obese, but some athletes aspire to gain weight (usually in the form of muscle) and diets can also be used to maintain a stable body weight. is the practice of ingesting food in a regulated fashion to achieve or maintain a controlled weight.