Today's emphasis on dieting has caused much anguish to the body, psyche and pocketbooks of some heavyweights in this country. As a result researchers have begun to look more closely at the link between body fat and disease to determine the real importance of diet therapy: Is the decision to go on a diet a health choice or a cosmetic cure?
At a recent nutrition conference in Newport Beach sponsored by the Dairy Council of California, Dr. C. Wayne Callaway, director of the Center for Clinical Nutrition, Department of Medicine, George Washington University, said location of fat in the body plays a significant role in health risk for some diseases.
Callaway's research indicates that it may be the distribution of a person's excess weight--no matter how much or little--and genetic and environmental factors that are really at issue when determining the potential for disease and the need for diet therapy. Physical appearance is the least consideration.
He explained that the male predisposition for coronary heart disease (in addition to genetics and environment), is affected by the fact that men's excess weight usually is carried in the abdomen and chest, whereas a woman tends to harbor her extra poundage in the hip area.
According to Callaway, many people who have a predetermined body type and metabolism based on family heritage and environmental climate may be unnecessarily starving and aerobicizing their bodies if their weight--because of its distribution--doesn't pose a potential for disease.
To support his claim, Callaway discussed the extent to which environmental and genetic factors influence body type and cited reasons why he feels it is important to re-evaluate our current standards for normal weight and at what point elevations of this figure imply increased risk of disease. He also dwelt on how these points affect dieting patterns and whether dieting is necessary at all.
Today's accepted norm for obesity is that it usually occurs when a person is 20% to 40% above the ideal weight range for his or her height and age group. Beyond its obvious cosmetic problems, being overweight is a health hazard with a variety of complications. It is implicated in the incidence of hypertension, gallbladder disease, cardiovascular disease and diabetes.
But the occurrence of any or all of these diseases is variable depending upon a host of other factors--environment, genetics and location of fat among them.
People are fat because of a number of factors. The most common one is that they are taking in more energy (calories) than they expend. But all fat people are not overeaters, Callaway contends.
Assumption Hard to Prove
"The usual first step in weight loss is to get people to eat less--the assumption is that people are fat because they are eating too much. But the assumption that fat people are eating more or grossly larger amounts than skinny people is really hard to prove," he said.
Environment is one reason people are fat, Callaway said. He conducted clinical studies that compared the most common human eating patterns (time, place, circumstances of eating) to see if they had any bearing on the rate of weight gain in individuals. He studied people who ate no breakfast and no lunch, those eating no breakfast, people whose total fat intake represented less than 10% of their day's total calories, those who ate three meals a day and "people whose major occupation was eating all day long."
Ten percent of the variation in the way these people's bodies expend energy could be accounted for by their eating patterns alone, not just by how much food they ate.
Family history is another factor. Callaway cited studies done with adopted children and identical twins. "As adults, adopted children had weights that correlated with the biological parents but not with the adopted parents." In the twins, identical pairs "were about twice as likely to be of similar weight than the non-identical ones, whether they were small or large or somewhere in between."
After a variety of studies, he concluded that about 80% of the way the body burned calories related to how much muscle and lean body mass each individual had--according to genetics. The remaining 20% was environmental, Callaway said.
Compound these two factors with a blurred picture of what is normal and the distinction between desirable weight and obesity becomes more distorted.
For the medical profession, what is considered normal is technically based on Metropolitan Life Insurance Co. weight tables, which were developed in 1942 based on the weight associated with the least mortality. (The tables have undergone revision several times, the latest in 1983.)