An explosion has occurred in the United States dieting industry over recent years with net annual profits now reaching 35 billion dollars. Surveys have revealed that approximately half of all Americans are attempting to lose weight at any given time. Yet according to one source(1)[ ], citizens are roughly the same weight now as they were in the 1960s. A 1993(2)[ ] study confirmed these discouraging facts; by surveying individuals who had dieted at least once in the past three years, researchers found that those who had lost 10-20% of their initial weight generally regained half of it after six months and two-thirds within two years.
So, what do these results mean for the average American who wants to lose weight? Is dieting basically a `hopeless cause'?
Researchers have found that traditional means of losing weight--particularly decreasing caloric intake--are harmful both physically and psychologically, and on the whole, aren't permanent means of weight loss. Recent literature(3) suggests that healthy women between the ages of 17 and 22 usually need between 1700 and 2500 calories each day, while men between 17 and 22 typically need 2000 to 4000 calories daily. When caloric intake falls much below these general guidelines, the body initiates a "starvation response." It lowers basal metabolic rates so that fewer calories are needed to function (resulting in fewer calories burned daily), the body begins to break down lean muscle (rather than fat) for energy, and it more readily converts digested foods into fat instead of muscle. Additionally, Yale researcher, Kelly Brownell, found that once this response has been initiated, it is increasingly easy to put weight back on quickly. He states that "it's as though dieting teaches the body a lesson. An organism that is repeatedly deprived of food increases its chances of survival if it learns to store food more efficiently when it is available. When food is once again scarce the body shuts down its [calorie-burning] furnace."(4)
Researchers have also found that psychological characteristics observed in dieters lead to unsuccessful weight loss. Dieters crave high-fat foods, and are likely to eat more of them than nondieters when these foods are available.(5) Also, when dieters finish their weight loss programs, they experience increased likelihoods of `bingeing' and quickly regaining the weight they have lost.
Though one's general body type and weight are believed to be inherited, these traits are not entirely fixed; you can make lifestyle changes that will enable you to achieve your most healthy weight. In addition to eating enough calories to avoid initiating the "starvation response," one should try to perform aerobic exercise such as walking, skating, cycling, aerobics, dancing, and jogging at least three times a week, and also participate in conditioning exercises. Scientists have found a positive correlation between muscle mass and metabolism, and have determined that one's metabolism increases after aerobic activity. Thus, by exercising in either form, one can expand the rate at which one's body burns calories. However, one must remember to increase caloric intake with increased exercise, or a "starvation response" may still occur. Also, it is important to remember not to take exercising to an unhealthy extreme.
Researchers also emphasize that it is important to eat a low-fat diet if one wishes to lose weight. Not only is low-fat food--such as bread, pasta, fruit and vegetables--generally more healthy than the fatty equivalent, but a greater proportion of it is `used up' by the body during digestion, and less is converted to fat for storage. Research from the University of Lausanne found that, "when fat is eaten, the body burns up only three percent of the calories in order to store the fat. In contrast, the calorie cost of storing carbohydrate as body fat amounts to 23 percent of the calories eaten."(6) What one must keep in mind though is that fat is an important part of one's diet and should not be cut out entirely. Further, if you choose to have a low-fat diet you must also maintain a balanced and healthy diet as outlined in the last issue of The Balance Beam.
To receive additional information on dieting or nutrition, or to schedule a no-cost appointment to discuss healthy food choices and nutrition, contact CAPS at 723-3785. If you have further questions, please call The Bridge at 723-3392.
1 Environmental Nutrition March 1992.
2 Consumer Reports June 1993, p. 353.
3 See "Dieting and You" by Laura Brainin-Rodriguez, R.D., M.S., M.P.H., produced for a Nutrition Education program sponsored by Stanford University Food Service and Cowell's Health Promotion Program.
4 Nutrition Action Healthletter March 1987, p. 10.
5 Environmental Nutrition 1992.
6 Nutrition Action Healthletter March 1987, p. 11.