Christine Telfer, age 14, of New Bedford, Mass., for her question:
WHAT CAUSES OBESITY?
Obesity is a body condition characterized by the storage of excessive amounts of fat in tissue beneath the skin and within other organs. Obesity is only rarely caused by disturbances of the endocrine system. It is not inherited, nor do fat babies necessarily grow up to be fat adults.
Obesity, the medical experts tell us, is usually a result of taking in more energy in food than one uses in activity. In other words, obesity is almost always caused by overeating.
Scientists have discovered that both obese and normal weight people go on eating binges, but people of normal weight reduce their intake afterward to compensate, whereas obese people do not.
Besides excess eating, obesity can also be caused by reduced activity and this often occurs in persons who are sedentary or bedridden.
All mammals, including humans, store body fat. In normal women, 25 percent of body weight is stored as fat. In normal men, 15 percent of body weight is stored as fat.
Depositing fat, which has twice the potential energy of carbohydrate or protein, is a way of storing energy for times of future need. Storage of greatly increased amounts of fat, however, is associated with impairment of health.
Data from insurance company records show that persons who are 30 percent or more overweight run measurably increased risks of disease, notably diabetes, cardiovascular and gall bladder disease, and arthritis. They also often encounter complications in surgery.
Many approaches to weight loss have been tried in obese people, with only limited success. Diet pills, containing the stimulant drug dextroamphetamine or one of its derivatives, became popular in the 1950s, but the Food and Drug Administration issued a series of
Many complex diets have been promoted for weight loss, but no scientific evidence exists that they are effective for grossly obese people.
Surgical procedures are sometimes recommended by doctors in extreme cases. These include intestinal bypass and gastric bypass. In the former operation a length of intestine is removed to reduce absorption of nutrients. This operation has been largely abandoned because it produced severe side effects, such as liver damage.
In the gastric bypass procedure most of the stomach is closed off with surgical staples. Only a small pouch remains to receive food, thereby greatly reducing a person's eating capacity.
A very obese person should consult a doctor and have a medical checkup before starting an extensive weight reduction program. Doctors often recommend that eating should be done only at certain times of the day or in certain places. A person must eat slowly and not too much.
If a man needs 3,000 calories a day to maintain his weight with his habits of life, he should eat only 2,000 calories a day to lose two pounds a week. It is generally dangerous to lose weight any faster.