By Jane E. Brody
Published: December 25, 1996
AMERICANS, having failed to lose weight in the fat-free-food era, are flocking back to a century-old regimen that has failed them repeatedly in the past: the high-protein, high-fat, low-carbohydrate diet currently advocated by Robert Atkins, Barry Sears and others who assert that it is carbohydrates, not fats, that are making people in this country fat.
This scheme was first promulgated in 1863 by a London undertaker named William Banting. It seems to resurface periodically under different rubrics, each time capturing the diet-book dollars of gullible Americans. Indeed, you might forget buying lottery tickets: writing a diet book with a gimmick is a surer route to riches.
Of Course It Works
Of course the low-carbohydrate diet works. If you cannot eat cookies, candy, cake, doughnuts, bagels, french fries, pie, ice cream and a host of other high-carbohydrate, high-calorie, high-fat favorites that people typically overeat, you are likely to consume fewer calories than you were eating before and you will undoubtedly lose weight. At first, the loss will be mainly water, because carbohydrates are the nutrients that hold water in your body.
A friend who had been on one of the low-carbohydrate diets for three months lapsed one day and ate a baked potato, which, she said, caused her to gain three pounds overnight. Now, the potato weighed only about half a pound, so even if she digested and assimilated every bit, it would not have been possible to gain three real pounds. What her dehydrated body gained was water, drawn in by the carbohydrates in the potato.
Furthermore, if you follow the Atkins regimen to the letter, substances called ketones will accumulate in your bloodstream and can make you slightly nauseated and light-headed and cause bad breath. This state is not exactly conducive to a hearty appetite, so chances are you will eat less than you might otherwise have of the high-protein, high-fat foods permitted on the diet. A ketogenic diet also has risks: excreting potassium and sodium along with the ketones can disrupt heart rhythms, an increase in uric acid can cause kidney stones, and a loss of calcium in urine raises the risk of osteoporosis.
The questions to ask yourself are not whether you can lose weight on this or any other diet, but whether you can stay on the diet indefinitely and keep the weight off permanently and whether you can do so without incurring other health risks. Where are the long-term follow-up studies to show that this is a once-and-for-all, safe and effective weight-loss program? Where are the people who have been on this diet for the 20-plus years since Dr. Atkins first published his ''diet revolution?'' Did they lose the desired amount of weight and keep it off? And are there any long-term ill effects?
No scientifically solid study has been published to support this diet scheme. And with the rapidly emerging evidence that a diet rich in plant foods -- grains, beans, fruits and vegetables -- is one of the best preventives of heart disease and cancer, a weight-loss scheme that greatly limits such foods is not exactly conducive to a long and healthy life.
The Body's Arithmetic
There is also no evidence that the human body violates the first law of thermodynamics, said Dr. Jules Hirsch, an obesity specialist at the Rockefeller University in New York. No diet that allows you to eat ''all you want'' of anything results in weight loss unless calories expended exceed calories consumed. Nor does it matter where the calories come from, Dr. Hirsch said. If anything, carbohydrates are preferable to fats as a calorie source for someone trying to lose weight because the body expends slightly more energy to metabolize them and because you can eat a larger volume of carbohydrates than you can of fats before exceeding your caloric needs.
So why, with the big push for grains, fruits and vegetables in recent years, have Americans become fatter than ever, with half the population now significantly overweight? Dr. Kelly Brownell, a psychologist who specializes in nutrition and eating disorders at Yale University, blames what he calls ''the toxic food environment we now live in: the ready availability of high-fat, good-tasting, heavily promoted, deceptively advertised foods.'' Americans are hard put to escape caloric overload when faced with mini-marts at service stations, drive-in windows at fast-food establishments, packaged fast-food meals and ''super-size'' servings of high-fat, high-calorie foods.
''The super-size fries and soft drink at McDonald's adds up to 800 calories and you haven't yet touched the burger,'' Dr. Brownell said. He noted that if laboratory animals were given free access to high-fat foods, they would eat them in preference to low-fat foods and they would get fat and sick.
Dr. Brownell recommends a societal effort to ''buffer people against toxic food messages, just the way we teach children not to smoke'' and to prohibit misleading advertising that, for example, calls a cereal that is 80 percent sugar ''part of a good breakfast.''
''People are not inevitably overweight, nor is their weight totally under personal control,'' Dr. Brownell said. ''There's an environment at work making a lot of this happen. It's not high-carbohydrate diets that are causing the increase in obesity. It's the ready availability of high-sugar, high-fat foods and the decline in physical activity.''
Although the average American today eats fewer calories than one did a century ago, Dr. Brownell pointed out that since 1900 the prevalence of obesity had more than doubled because physical activity had declined so substantially. Despite the exercise boom, relatively few Americans do anything to make up for the lack of activity in their workaday lives.
Dr. Brownell maintains that much of the success of a weight-loss program is determined by ''what goes on in your head.'' For most people, starting with an ''unrealistic esthetic ideal or the height-weight tables as the goal is likely to result in frustration, disappointment and giving up.'' Instead, he recommends setting a more achievable goal of losing about 10 percent of one's weight. After achieving that loss and doing everything possible to make sure it is permanent, then you can decide whether you want to and can try to lose more.
Biology seems to work against an obese person who loses a significant amount of weight, Dr. Hirsch noted. The body becomes more efficient, using fewer calories to perform a given task. The only way to counter that fundamental fact is through regular physical activity that increases muscle mass at the expense of body fat, which will raise the number of calories the body burns at all times, at rest or at work.
Drawing. (Victoria Roberts)