Weight and Health: feel better
and look better
Americans trying to lose weight have plenty of
company. According to a 1995 report from the Institute of Medicine
(IOM), tens of millions of Americans are dieting at any given time,
spending more than $33 billion yearly on weight-reduction products,
such as diet foods and drinks.
Yet, studies over the last two decades by the National Center for
Health Statistics show that obesity in the United States is actually
on the rise. Today, approximately 35 percent of women and 31 percent
of men age 20 and older are considered obese, up from approximately
30 percent and 25 percent, respectively, in 1980.
The words obesity and overweight are generally used interchangeably.
However, according to the IOM report, their technical meanings are
not identical. Overweight refers to an excess of body weight that
includes all tissues, such as fat, bone and muscle. Obesity refers
specifically to an excess of body fat. It is possible to be
overweight without being obese, as in the case of a body builder who
has a substantial amount of muscle mass. It is possible to be obese
without being overweight, as in the case of a very sedentary person
who is within the desirable weight range but who nevertheless has an
excess of body fat. However, most overweight people are also obese
and vice versa. Men with more than 25 percent and women with more
than 30 percent body fat are considered obese.
Many people who diet fail to lose weight--or, if they do lose, fail
to maintain the lower weight over the long term. Obesity is "a
complex, multifactorial disease of appetite regulation and energy
metabolism."
Because many factors affect how much or how little food a person
eats and how that food is metabolized, or processed, by the body,
losing weight is not simple. For example, recent studies suggest a
role for genetic makeup in obesity. This area is still
controversial, and more studies will be needed before scientists can
say with certainty that a person's genes may set limits on how much
weight can be lost and maintained.
Yet many people persist in seeking simple cures to this complex
health problem. Lured by fad diets or pills that promise a quick and
easy path to thinness, they end up disappointed when they regain
lost weight.
No Shortcuts
"There are no shortcuts--no magic pills," says Lori Love, M.D.,
Ph.D., of the Food and Drug Administration's Center for Food Safety
and Applied Nutrition. Losing weight sensibly and safely requires a
multifaceted approach that includes setting reasonable weight-loss
goals, changing eating habits, and getting adequate exercise.
Appetite suppressants (diet pills) or other products may help some
people over the short term, but they are not a substitute for
adopting healthful eating habits over the long term.
The first step in losing weight safely is to determine a realistic
weight goal. The table, at right, developed by the U.S. Department
of Agriculture and the Department of Health and Human Services,
offers a range of suggested weights for adults based on their
height.
A physician, dietitian or nutritionist also can help you set a
reasonable goal. To reach the goal safely, plan to lose 1 to 2
pounds weekly by consuming approximately 300 to 500 fewer calories
daily than usual (women and inactive men generally need to consume
approximately 2,000 calories to maintain weight; men and very active
women may consume up to 2,500 calories daily).
Moderation, Variety and Balance
After determining a reasonable goal weight, devise an eating plan
based on the cornerstones of healthful eating--moderation, variety
and balance, suggests Victor Herbert, M.D., J.D., professor of
medicine and director of the Nutrition Center at the Mount Sinai
School of Medicine and Bronx VA Medical Centers in New York City,
and member of the board of directors of the National Council Against
Health Fraud.
"Moderation means not eating too much or too little of any
particular food or nutrient; variety means eating as wide a variety
as possible from each, and within each, of the five basic food
groups; and balance refers to the balance achieved by following
moderation and variety, as well as the balance of calories consumed
versus calories expended," he explains. To lose weight, fewer
calories should be consumed than expended; to maintain weight loss,
the number of calories consumed and expended should be about the
same.
Because fat is the most concentrated source of calories (9 calories
per gram compared to 4 calories per gram for carbohydrate and
protein), it is usually the focus of weight-maintenance and
weight-loss diets. Limiting fat intake alone will likely limit
calories, as well. Just as for the general population,
weight-conscious consumers should limit fat intake to no more than
30 percent of total calories, according to the Dietary Guidelines
for Americans.
Alcoholic beverages also are a source of calories (7 per gram of
alcohol). Twelve ounces of regular beer, for example, provides 150
calories; the same amount of "light" beer, 105 calories. Five ounces
of wine or 1.5 ounces of 80-proof distilled spirits provide 100
calories. But alcohol provides few, if any, nutrients, so if you
drink alcoholic beverages and want to reduce your weight, consider
reducing or eliminating your alcohol intake.
In selecting your diet, follow the five basic food groups and the
recommended number of servings from each as incorporated into the
Food Guide Pyramid developed by USDA and HHS. These groups are (1)
bread, cereal, pasta, and rice; (2) vegetables; (3) fruits; (4)
milk, yogurt and cheese; and (5) meat, poultry, fish, dry beans,
eggs, and nuts. A sixth group (fats, oils and sweets) consists
mainly of items that are pleasing to the palate but high in fat
and/or calories; these should be eaten in moderation.
Avoid low-calorie fad diets that exclude whole categories of food
such as carbohydrates (bread and pasta) or proteins (meat and
poultry). These diets may be harmful because they generally do not
include all nutrients necessary for good health. "Every fad diet
that demands an unusual eating pattern, such as emphasizing only a
few types of foods, deviates from one or more of the guidelines of
moderation, variety and balance," says Herbert. "The greater the
deviation, the more harmful the diet is likely to be."
Using the Food Label
To help consumers plan a healthful diet, FDA and USDA have revamped
food labels. By law, most food labels now must display a Nutrition
Facts panel containing information about how the food can fit into
an overall daily diet. Nutrition Facts state how much saturated fat,
cholesterol, fiber, and certain nutrients are contained in each
serving.
On the food label, %Daily Value shows what percentage of a given
nutrient is provided in one portion for daily diets of 2,000
calories.
Whether or not a given food fits into a weight-loss diet depends on
what other foods you eat that day. For most people, the goal is to
select a variety of foods that together add up to approximately 100
percent of the Daily Value for total carbohydrate, dietary fiber,
vitamins, and minerals; total fat, cholesterol and sodium each may
add up to less than 100 percent.
Foods that claim to contain fewer calories or less fat than similar
servings of similar products must show the difference on the label.
For example, on a container of low-fat cottage cheese, the label
would show that a serving of the low-fat product contains 80
calories and 1.5 grams of fat while regular cottage cheese contains
120 calories and 5 grams of fat per serving.
Camille Brewer, a registered dietitian and nutritionist in FDA's
Center for Food Safety and Applied Nutrition, advises caution,
however, when choosing foods that are labeled "fat-free" and
"low-fat." Some of these foods, like "low-fat" cakes and cookies,
still may be high in calories because of added sugars. So dieters
should always check the Nutrition Facts panel to get complete
information, she says.
Look for foods high in fiber, such as fruits, vegetables, legumes
and whole grains. Fiber can be an important aid in weight
maintenance because eating enough of it can help make a person feel
full and thus not eat as much.
Exercise
Regular exercise is important for overall health, as well as for
losing and maintaining weight. There is evidence to suggest that
body fat distribution affects health risks. For example, excess fat
in the abdominal area (as opposed to hips and thighs) is associated
with greater risk for high blood pressure, diabetes, early heart
disease, and certain types of cancer. Vigorous exercise can reduce
abdominal fat and thus lower the risk of these diseases.
The Dietary Guidelines for Americans recommends a half hour or more
of moderate physical activity on most days, preferably every day.
The activity can include brisk walking, calisthenics, home care,
gardening, moderate sports exercise, and dancing. Regular exercise
can help the body use up calories consumed daily, as well as excess
calories stored as fat. Weight-bearing exercises also help tone
muscles and may reduce the risk of osteoporosis.
OTC Diet Pills
The 1991/1992 Weight Loss Practices Survey, sponsored by FDA and the
National Heart, Lung, and Blood Institute, found that 5 percent of
women and 2 percent of men trying to lose weight use diet pills.
Products considered by FDA to be over-the-counter weight control
drugs are primarily those containing the active ingredient
phenylpropanolamine (PPA), such as Dexatrim and Acutrim. PPA is
available OTC for weight control in a 75-mg controlled-release
dosage form. The medicine should be used in combination with a
restricted diet and exercise.
Using diet pills
containing PPA will not make a big difference in the rate of weight
loss, says Robert Sherman of FDA's Office of OTC Drug Evaluation.
"Even the best studies show only about a half pound greater weight
loss per week using PPA combined with diet and exercise," he adds.
Sherman cautions that the recommended dosage of these pills should
not be exceeded because of the risk of possible adverse effects,
such as elevated blood pressure and heart palpitations.
Since PPA is also used as a nasal decongestant in over-the-counter
cough and cold products, consumers should read the labels of OTC
decongestants to see if they contain PPA. They should not take PPA
in two products labeled for different uses.
Sherman notes that FDA has received a small number of reports
indicating that PPA use might be associated with an increased risk
of stroke. A large-scale safety study was begun in September 1994 to
explore the possibility. Based on available data, the agency does
not believe that an increased risk of stroke is a concern when PPA
is used at recommended dosages.
Rx Drugs
FDA has approved several prescription drugs for obesity. The newest
is Xenical (orlistat),
which FDA approved in April 1999.
Xenical is the first in a new class of anti-obesity drugs known as
lipase inhibitors. Lipase is the enzyme that breaks down fat for use
by the body. Xenical interferes with lipase function, decreasing fat
absorption by 30 percent. Since undigested fats are not absorbed,
there is less calorie intake, which may have a positive effect on
weight control.
Other approved anti-obesity prescription drugs available on the
market include:
Dexedrine and other amphetamines
Ionamin and Adipex-P (phentermine), Sanorex (mazindol), Tenuate (diethylpropion),
Prelu-2 (phendimetrazine) and other amphetamine derivatives
Meridia (sibutramine).
In mostly short-term studies of obese adults following a
calorie-restricted diet, those who took the appetite suppressants
lost more weight on average than those who took a placebo. The
amount of weight lost varied from study to study.
FDA approved the drugs only for use with calorie-restricted diets.
The drugs are "not magic pills," warns Leo Lutwak, M.D., Ph.D., of
FDA's division of metabolism and endocrine drug products. "They
don't work unless you make dietary and exercise changes."
While obesity may be associated with other serious diseases, studies
have never shown that weight loss produced with the use of
prescription weight-loss drugs benefits obesity-associated
conditions. However, changes in diet and activity may improve
associated diseases, such as diabetes and high blood pressure, even
with only modest changes in weight, Lutwak says.
Weight-Loss Programs
Many people turn to weight-loss programs for help in planning a
daily diet and changing lifestyle habits. The IOM report provides
guidelines for evaluating the potential effectiveness of such
programs.
"To improve their chances for success, consumers should choose
programs that focus on long-term weight management; provide
instruction in healthful eating, increasing activity, and improving
self-esteem; and explain thoroughly the potential health risks from
weight loss," according to the report. Consumers should also demand
evidence of success. If it is absent or consists primarily of
testimonials or other anecdotal evidence, "the program should be
viewed with suspicion."
The basic tenet of weight loss--to eat fewer calories than you burn
and to stay active--is easy to say but, like most lifestyle changes,
not so easy to do. With realistic goals, and a commitment to losing
weight slowly, safely and sensibly, the chances of long-term success
improve dramatically. Why not try a prescription diet pill to
help you achieve your goals? |
