Drop that fat! How to and how not to lose weight.

Drop That Fat!

If you're trying to lose weight (or even just thinking about it), you're in good company! According to the American Dietetic Association, nearly half of all women and more than one fourth of all men in the United States are on some sort of diet. Is this degree of concern really warranted? In his 1988 Report on Nutrition and Health, former U.S. surgeon general C. Everett Koop, M.D., states that overweight "is one of the most prevalent diet-related problems in the United States."

Overweight poses serious health risks. It increases risk of high blood pressure, diabetes, certain types of cancer, osteoarthritis, and gallstones. Because overweight persons tend to have higher levels of low-density lipoprotein cholesterol, or LDL (the "bad" cholesterol), and lower levels of high-density lipoprotein cholesterol, or HDL (the "good" cholesterol), they are also at higher risk of heart attack. And because of the strong pressures from society to be thin, overweight people often suffer feelings of guilt, depression, anxiety, and low self-esteem.

Health objectives for the nation. Earlier this year the U.S. Department of Health and Human Services released the publication "Promoting Health/Preventing Disease: Year 2000 Objectives for the Nation." The document outlines more than 400 specific objectives for improving the nation's health, including three relating specifically to obesity. Of these three objectives, the first two set goals for reducing the percent of American adults and adolescents who are overweight:

1. Reduce overweight among people ages 20 through 74 to a prevalence of no more than 20 percent.

2. Reduce overweight among adolescents ages 12 through 17 to a prevalence of less than 15 percent.

Estimates of overweight among American men and women ages 20 through 74 are 24 and 27 percent, respectively, while 22 percent of American teens are considered overweight. Considerable improvement in the shape of Americans will have to take place before we can meet these goals.

The third and final obesity objective relates to the approach overweight people take to manage their weight.

3. Increase to at least 75 percent the proportion of overweight people age 12 and older who have adopted sound dietary practices combined with physical activity to achieve weight reduction.

Currently only about 30 percent of overweight women and 25 percent of overweight men aged 18 years and older have adopted "sound" practices to achieve weight reduction.

What is overweight? Methods to assess weight include height-weight tables, relative weight, body mass index, and percent body fat. Height-weight tables are the most familiar yet most imprecise method of assessing body weight status. Relative weight, a somewhat better method, is simply your current weight divided by the average recommended weight for your height taken from a height-weight chart and then multiplied by 100. A relative weight of 120 percent or more (20 percent or more overweight) is a common definition of overweight.

A still better indicator of overweight that is used in surveys and large research projects is body mass index (BMI). BMI, for example, was used in determining the percent of overweight American adults and adolescents mentioned in the objectives above. A simple method of discovering your BMI is using the "nomogram" in Figure 1. You can compare your results with the accompanying norms. The health risks associated with overweight begin in the BMI range of 25 to 30 kilograms per meter.

While determination of percent body fat is the most accurate method to assess obesity, it has certain drawbacks that make it unsuitable for use in large population groups. Underwater weighing requires expensive and bulky equipment, skinfold measurements must be taken by an experienced technician, and other techniques either require highly sophisticated equipment or are still being perfected.

The causes of overweight. Investigation into the causes of obesity have narrowed the search down to three areas: genetic and parental influences, low energy expenditure, and high energy intake. Research indicates that because of genetic influences some people may be more prone to overweight than others, and that these people have to be careful with their dietary and exercise habits to counteract inherited tendencies. Overall, though, cultural, environmental, and lifestyle factors play a more important role in determining body weight than do genetic influences.

Regular physical activity is essential for good health, but compared with diet it plays a relatively minor role in weight control. (See "Can You Exercise Your Way to Ideal Weight?" in this issue.)

The most powerful cause of overweight appears to be high energy intake, especially in the form of fat calories. Scientists at Cornell University found that when persons were allowed to eat all they desired throughout the day from three diets differing only in the amount of fat each diet contained, energy consumption was 30 percent higher on a high-fat-diet (45 to 50 percent of calories as fat) than on a low-fat diet (15 to 20 percent of calories as fat). While eating the low-fat diet for two weeks, subjects lost nearly a pound without even trying. The same subjects gained more than half a pound after two weeks on the high-fat diet.

At the University of Alabama, 20 persons were randomly assigned to either a low-fat or high-fat diet for five days and then switched to the other diet for another five days. Subject reported finding both diets equally acceptable. Despite being instructed to eat as they desired, they ate nearly twice as many calories on the high-fat diet than on the low-fat diet.

Are calories from the fat we eat handled any differently by the body than extra calories from carbohydrate? Yes. It is easier for our bodies to convert dietary fat into body fat than to change carbohydrate into body fat. In other words, gaining weight is easier eating fat calories than eating extra carbohydrates calories. Thus the form in which we eat our calories (either as carbohydrates, protein, or fat) may be almost as important as how many calories we eat!

Commercial weight management programs. A smorgasbord of weight-loss diets, books, and programs has resulted from our national preoccupation with weight loss. In 1989 alone 65 million Americans spent $32.4 billion on diets and related products and services. Growth and profits have been especially high in commercial weight-loss programs, whose estimated revenues for 1989 were $1.8 billion.

Examples of commercial programs available for the mildly overweight (BMI of 25 to 30 kilograms per meter) are Weight Watchers, Diet Center, Nutri/System, and Jenny Craig Weight Loss Centers. All provide varying degrees of group support and individual counseling. Class topics vary but in general include nutrition education, handling stress, building self-esteem, exercise, and managing eating behavior and social situations. Costs range from a low $30 to join and $9 a week (Weight Watchers) to potentially more than $300 (Nutri/System), with prepackaged food costing extra. Weight Watchers and Diet Center teach meal planning according to the four food groups or exchange lists. Food is store-bought, and recommended daily calorie intake is from 1,000 to 1,400. Nutri/System and Jenny Craig provide patrons with their own prepackaged foods averaging $50 to $60 a week with energy levels ranging from 1,000 to 1,100 calories per day. While these prepackaged plans provide diets that are low-fat and high-fiber, and thus healthy, they don't adequately teach clients how to make wise food choices once they're off the diet and back to eating "real food."

These programs are not without their problems. Most people entering programs drop out before completing them. Those who do finish lose weight, but most gain much, if not all, of it back within the next year or so. A study by the U.S. Food and Drug Administration showed that fewer than 2 percent of dieters retain their desired weight seven years after undertaking a weight loss program.

For the few who are moderately overweight (BMI of 30 to 40 kilograms per meter) desiring a more aggressive approach, there are very low-calorie diets (VLCD). The Optifast and Medifast programs are examples of VLCDs. A partial fast involves consuming several vitamin-and mineral-fortified liquid protein drinks and lots of water each day. No solid food is eaten during this time. With a daily energy intake of 420 to 800 calories, weight loss is rapid in the first few weeks, slows midway through the program, and averages about three to 10 pounds a week. After 12 weeks of the liquid diet, there are seven weeks of re-introduction to food, and an additional six weeks of stabilization. Accompanying this are classes in behavior modification, individual counseling with dietitians and psychologists, and monitoring of health by physicians. This is followed by six months of relapse prevention.

Very-low-calorie diets have their problems, too. In several recent studies of VLCD programs, more than half the dieters dropped out before completing the fasting phase of the program, and much of the weight lost was regained. The most successful VLCD programs are those giving much attention to nutrition and psychological counseling, behavior modification, and having a long follow-up period.

The weight-loss lost in VLCDs not only carries a hefty dollar figure ($3,000 to $3,600 for the Optifast program), but often results in higher than desired losses in lean body tissue. Weight lost in dieting comes from both fat and lean body tissue. When diets are only marginally less than normal energy needs (for example, 1,200 calories a day), fat and lean body tissue (primarily muscle) account for about 75 percent and 25 percent of weight lost, respectively. However, as much as half of the weight lost with VLCDs can come from lean body tissue. The problem is that fat is much easier to gain than lean body mass and when weight is regained after a program, most of it is fat.

A recommended approach. Nine out of 10 overweight people are mildly overweight. The recommended approach for these is a conservative program of mild calorie restriction (primarily using less fat in the diet), regular physical activity, and technique to change the way we eat and think about food (see box on behavior modification). A healthy weight loss goal would be 1 percent of your total weight per week until you reach your target weight.

For people preferring a commercial program, I would suggest Weight Watchers. It is affordable, convenient, comprehensive, and designed to meet a variety of lifestyles. It offers a nutritious, state-of-the-art food plan utilizing everyday food, group support, behavior modification, and a maintenance plan. Also available are the Inner Circle, for persons desiring small group participation, and At Work, which meets at businesses.

Since most people need to lose less than 30 pounds, they could easily manage on the following conservative program: * Avoid crash weight loss programs or any that seem to good to be true, because they probably are! * Slowly introduce changes into your diet and lifestyle, for these are more likely to be well thought out and permanent. * Identify foods and dishes in your diet that are high in fat and gradually work toward reducing the fat content of these by substituting lower-fat ingredients (nonfat or low-fat dairy products, leaner cuts of meat if you use it, and less oil, butter, and margarine). * In meal planning, emphasize fruits, vegetables, whole-grains, and beans - preferably prepared with little or no added fat. * Make breakfast and lunch whole-some meals, and the evening meal, if eaten, relatively light. * Drink plenty of water between meals instead of snacking. * If you do snack, stick with fresh vegetables and fruits, which are low in calories and fat. * Make all meals elegant and enjoyable social occasions. * Gradually experiment with and introduce low-fat dishes into your meals.

As we wrap up the twentieth century and enter the twenty-first, I hope that our frustration from lack of a "magic bullet" for overweight matures into a renewed sense of personal responsibility and yields to greater exercise of personal choice in what and how we eat and how we live. I hope that prevention of overweight will be seen as the "treatment of choice," and that enlightened parents will guide their children in making healthful food choices conducive to weight management. Fraudulent and exploitative quick fixes to overweight will, no doubt, continue to be promoted and tried. Ultimately, though, our success as a nation in meeting the year 2000 objectives for overweight will largely depend on applying current knowledge of the causes and management of overweight and on being thoughtful and supportive of those who daily struggle against overweight.