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Losing Weight: More Than Counting Calories
By Linda Bren
This article originally appeared in the January-February 2002 FDA Consumer and contains revisions made in April 2002.
Americans are getting fatter. We're putting on the pounds at an alarmingly rapid rate. And we're sacrificing our health for the sake of supersize portions, biggie drinks, and two-for-one value meals, obesity researchers say.
More than 60 percent of U.S. adults are either overweight or obese, according to the Centers for Disease Control and Prevention (CDC). While the number of overweight people has been slowly climbing since the 1980s, the number of obese adults has nearly doubled since then.
No Laughing Matter
Excess weight and physical inactivity account for more than 300,000 premature deaths each year in the United States, second only to deaths related to smoking, says the CDC. People who are overweight or obese are more likely to develop heart disease, stroke, high blood pressure, diabetes, gallbladder disease, and joint pain caused by excess uric acid (gout). Excess weight can also cause interrupted breathing during sleep (sleep apnea) and wearing away of the joints (osteoarthritis).
Carrying extra weight means carrying an extra risk for certain types of cancer. "[Our] researchers have concluded that obesity increases the risk for many of the most common cancers worldwide, and perhaps cancer in general," says Melanie Polk, R.D., director of nutrition education at the American Institute for Cancer Research (AICR), a nonprofit research and education organization in Washington, D.C.
In their review of more than 100 studies and international reports on obesity and cancer risk, completed in October 2001, researchers at the AICR concluded that obesity is consistently linked to post-menopausal breast cancer, colon cancer, endometrial cancer, prostate cancer, and kidney cancer.
To address the public health epidemic of being overweight or obese, former Surgeon General David Satcher issued a "call to action" in December 2001. The Surgeon General's Call To Action To Prevent and Decrease Overweight and Obesity outlined strategies that communities can use in helping to address the problems. Those options included requiring physical education at all school grades, providing more healthy food options on school campuses, and providing safe and accessible recreational facilities for residents of all ages.
Overweight refers to an excess of body weight, but not necessarily body fat. Obesity means an excessively high proportion of body fat. Health professionals use a measurement called body mass index (BMI) to classify an adult's weight as healthy, overweight, or obese (see the BMI chart, "Are You at a Healthy Weight?"). BMI describes body weight relative to height and is correlated with total body fat content in most adults.
To get your approximate BMI, multiply your weight in pounds by 703, then divide the result by your height in inches, and divide that result by your height in inches a second time. (Or you can use the interactive BMI calculator at www.nhlbisupport.com/bmi/bmicalc.htm.)
A BMI from 18.5 up to 25 is considered in the healthy range, from 25 up to 30 is overweight, and 30 or higher is obese. Generally, the higher a person's BMI, the greater the risk for health problems, according to the National Heart, Lung and Blood Institute (NHLBI). However, there are some exceptions. For example, very muscular people, like body builders, may have a BMI greater than 25 or even 30, but this reflects increased muscle rather than fat. "It is excess body fat that leads to the health problems such as type 2 diabetes, high blood pressure, and high cholesterol," says Eric Colman, M.D., of the Food and Drug Administration's Division of Metabolic and Endocrine Drug Products.
In addition to a high BMI, having excess abdominal body fat is a health risk. Men with a waist of more than 40 inches around and women with a waist of 35 inches or more are at risk for health problems.
Obesity, once thought by many to be a moral failing, is now often classified as a disease. The NHLBI calls it a complex chronic disease involving social, behavioral, cultural, physiological, metabolic, and genetic factors. Although experts may have different theories on how and why people become overweight, they generally agree that the key to losing weight is a simple message: Eat less and move more. Your body needs to burn more calories than you take in.
A popular weight-loss myth is that everyone who loses weight eventually gains it back, says Rena Wing, Ph.D., a professor of psychiatry at Brown Medical School in Providence, R.I. Wing, the co-developer of a research study known as the National Weight Control Registry, has worked to deflate this myth.
Tucked away in the registry's database is information about the weight-control behaviors of more than 3,000 American adults who have lost an average of 60 pounds and have kept it off for an average of six years.
How do they do it?
These successful losers report four common behaviors, says Wing. They eat a low-fat, high-carbohydrate diet, they monitor themselves by weighing in frequently, they are very physically active, and they eat breakfast. Eating breakfast every day is contrary to the typical pattern for the average overweight person who is trying to diet, says Wing. "They get up in the morning and say 'I'm going to start my diet today,' and they eat little or no breakfast and a light lunch. Then they get hungry and consume most of their calories late in the day. Successful weight losers have managed to change this pattern."
Six years after their weight loss, most of the registry's successful losers still report eating a low-calorie, low-fat diet, with about 24 percent of calories from fat. (The Dietary Guidelines for Americans recommend no more than 30 percent of daily calories from fat.) They also exercise for about an hour or more a day, expending about 2,800 calories per week on a variety of activities. This is equivalent to walking 28 miles a week, or four miles a day, says Wing.
Wing also reports that more than 70 percent of the registry's weight losers became overweight before age 18.
Although Barbara Croft of Columbus, Ohio, was not an overweight child, she gained weight once she left home and started cooking for herself. Replacing the plain and simple meals she had as a child with pizza, sodas, and meat and vegetables laden with sauces, the 5-foot-5-inch Croft worked her way up to 350 pounds. "I always ate from all the food groups--I just ate huge portions and I ate in between meals," says Croft.
When she was diagnosed with type 2 diabetes in February 1999, Croft got scared. "I worried about the health consequences--about going blind. I already have a little numbness in my feet."
Croft went on a diet and lost 200 pounds in 19 months. She has kept it off for a year and a half. "This is the third time I've lost over 100 pounds," says the 52-year-old, 150-pound Croft, "but this is the longest I've been able to keep the weight off." In her two previous weight losses, Croft ate nutritious meals, but didn't exercise. This time, she started walking for exercise, but could only walk about a block at first. "My husband went with me because he was afraid I wouldn't make it," she says. Now, Croft walks on a treadmill for 50 minutes a day--25 minutes each morning and night.
She still eats balanced meals, but restricts her portions. And she always eats breakfast. "I have Egg Beaters, two pieces of low-calorie bread, fruit, decaf coffee, and 8 ounces of water." Croft dines out almost every night, typically eating half her dinner of grilled chicken or salmon and a vegetable or salad. She sends the other half back, so she isn't tempted to overeat.
"Losing the weight was easy--maintaining it is much harder," says Croft.
Croft had tried commercial weight-loss programs in the past, but this last time she did it on her own. "You have to find out what works for you," she says. "If I eat butter or cheese, that seems to do me in. Beef is also a problem."
Croft's diabetes is under control now without medication. And she says her knees don't hurt anymore, she can buy clothes in a regular store, and she started traveling again now that she can fit into an airplane seat.
Setting a Goal
The first step to weight loss is setting a realistic goal. By using a BMI chart and consulting with your health-care provider, you can determine what is a healthy weight for you.
Studies show that you can improve your health with just a small amount of weight loss. "We know that physical activity in combination with reduced calorie consumption can lead to the 5 to 10 percent weight loss necessary to achieve remission of the obesity-associated complications," says William Dietz, M.D., Ph.D., director of the Division of Nutrition and Physical Activity at the CDC. "Even these moderate weight losses can improve blood pressure and help control diabetes and high cholesterol in obese or overweight adults."
To reach your goal safely, plan to lose weight gradually. A weight loss of one-half to 2 pounds a week is usually safe, according to the Dietary Guidelines for Americans. This can be achieved by decreasing the calories eaten or increasing the calories used by 250 to 1,000 calories per day, depending on current calorie intake. (Some people with serious health problems due to obesity may lose weight more rapidly under a doctor's supervision.) If you plan to lose more than 15 to 20 pounds, have any health problems, or take medication on a regular basis, a doctor should evaluate you before you begin a weight-loss program.
Changing Eating Habits
Dieting may conjure up visions of eating little but lettuce and sprouts--but you can enjoy all foods as part of a healthy diet as long as you don't overdo it on fat (especially saturated fat), protein, sugars, and alcohol. To be successful at losing weight, you need to change your lifestyle--not just go on a diet, experts say.
Limit portion sizes, especially of foods high in calories, such as cookies, cakes and other sweets; french fries; and fats, oils and spreads. Reducing dietary fat alone--without reducing calories--will not produce weight loss, according to the NHLBI's guidelines on treating overweight and obesity in adults.
Use the Food Guide Pyramid, developed by the U.S. Department of Agriculture (USDA) and the Department of Health and Human Services, to help you choose a healthful assortment of foods that includes vegetables, fruits, grains (especially whole grains), fat-free milk, and fish, lean meat, poultry, or beans. Choose foods naturally high in fiber, such as fruits, vegetables, legumes (such as beans and lentils), and whole grains. The high fiber content of many of these foods may help you to feel full with fewer calories.
All calorie sources are not created equal. Carbohydrate and protein have about 4 calories per gram, but fat has more than twice that amount (9 calories per gram). Just as for the general population, weight-conscious consumers should aim for a daily fat intake of no more than 30 percent of total calories.
Keep your intake of saturated fat at less than 10 percent of calories. Saturated fats increase the risk for heart disease by raising blood cholesterol. Foods high in saturated fats include high-fat dairy products (like cheese, whole milk, cream, butter, and regular ice cream), fatty fresh and processed meats, the skin and fat of poultry, lard, palm oil, and coconut oil.
If you drink alcoholic beverages, do so in moderation. Alcoholic beverages supply calories but few nutrients. A 12-ounce regular beer contains about 150 calories, a 5-ounce glass of wine about 100 calories, and 1.5 ounces of 80-proof distilled spirits about 100 calories.
Limit your use of beverages and foods that are high in added sugars--those added to foods in processing or preparation, not the naturally occurring sugars in foods such as fruit or milk. Foods containing added sugars provide calories, but may have few vitamins and minerals. In the United States, the major sources of added sugars include non-diet soft drinks, sweets and candies, cakes and cookies, and fruit drinks and fruitades.
Using the Food Label
Under regulations from the FDA and the USDA, the food label, found on almost all processed foods, offers more complete, useful and accurate nutrition information than ever before. Even when restricting calories and portions, you can use the part of the food label called the Nutrition Facts panel to make sure you get all the essential nutrients for good health.
You'll find the serving size and the number of servings per package listed at the top of the Nutrition Facts panel. The serving size affects all the nutrient amounts listed on the panel. For example, if there is one cup in a serving and the package contains two servings, you need to double the calories and other nutrient numbers if you eat the whole package. Many items sold as single portions--like a 20-ounce soft drink, a 3-ounce bag of chips, and a large bagel--actually provide two or more servings.
"If you zero in on the 'amount per serving' section of the Nutrition Facts panel, you can tell at a glance how many calories a serving has and whether a food is high in total fat, saturated fat, cholesterol, and sodium," says Naomi Kulakow, coordinator of food labeling education in the FDA's Center for Food Safety and Applied Nutrition. "These are items you should think about limiting in your diet."
The Nutrition Facts panel also shows how much dietary fiber, vitamin A, vitamin C, calcium, and iron are contained in a serving. These are nutrients you need for good health.
Also listed on the Nutrition Facts panel are the amounts of carbohydrates, protein, and sugars contained in a serving. Use the panel to compare the amount of total sugars among similar products, and try to choose ones lower in sugars.
In addition to listing some nutrients by weight, the panel also gives this information as a Percent Daily Value (%DV). The %DV shows how a serving of a food fits in with recommendations for a healthful diet and allows consumers to make comparisons between similar products.
For example, shoppers can use the %DV figures to find out which frozen dinner is lower in saturated fat--particularly when it involves a comparative nutritional claim, such as reduced-fat. "You don't need to know the precise definition of 'low' or 'reduced,'" says Kulakow. "Just look at the Percent Daily Value and see which is higher or lower in the nutrient you are interested in." Foods with 5 percent or less of the Daily Value are considered low in a nutrient, while those with 20 percent or more are high in the nutrient.
The %DVs are based on a 2,000-calorie daily diet. But even if you eat less than 2,000 calories, the %DV can be used to determine whether a food is high or low in a particular nutrient.
"People use the food label too often to just restrict calories and fat--not to get enough nutrients," says Kulakow. While restricting calories is important for weight loss, "most people have no idea how many calories they consume every day--especially if they eat out." The %DV gives you a frame of reference and can be used to make dietary trade-offs, says Kulakow. "For example, if you eat a favorite food that's high in fat at one meal, balance it with low-fat foods at other times of the day."
Kulakow advises caution when choosing foods that are labeled "fat-free" and "low-fat." Fat-free doesn't mean calorie-free. To make a food tastier, sometimes extra sugars are added, which adds calories (see "Fat-Free vs. Regular Calorie Comparison"). So dieters should always check the Nutrition Facts panel to get complete information, says Kulakow.
For further guidance on using the Nutrition Facts panel, visit FDA's Center for Food Safety and Applied Nutrition.
Increasing Physical Activity
Most health experts recommend a combination of a reduced-calorie diet and increased physical activity for weight loss. Most adults should get at least 30 minutes and children should get 60 minutes of moderate physical activity on most, and preferably all, days of the week. But fewer than 1 in 3 U.S. adults gets the recommended amount of physical activity, according to The Surgeon General's Call To Action To Prevent and Decrease Overweight and Obesity.
In addition to helping to control weight, physical activity decreases the risk of dying from coronary heart disease and reduces the risk of developing diabetes, hypertension, and colon cancer. Researchers also have found that daily physical activity may help a person lose weight by partially lessening the slow-down in metabolism that occurs during weight loss.
Exercise does not have to be strenuous to be beneficial. And some studies show that short sessions of exercise several times a day are just as effective at burning calories and improving health as one long session.
To lose weight and to maintain a healthy weight after weight loss, many adults will likely need to do more than 30 minutes of moderate physical activity daily.
Prescription Weight-Loss Drugs
For obese people who have difficulty losing weight through diet and exercise alone, there are a number of FDA-approved prescription drugs that may help. "On average, individuals who use weight-loss drugs lose about 5 percent to 10 percent of their original weight, though some will lose less and some more," says the FDA's Colman.
All of the prescription weight-loss drugs work by suppressing the appetite except for Xenical (orlistat). Approved by the FDA in 1999, Xenical is the first in a new class of anti-obesity drugs known as lipase inhibitors. Lipase is the enzyme that breaks down dietary fat for use by the body. Xenical interferes with lipase function, decreasing dietary fat absorption by 30 percent. Because the undigested fats are not absorbed, fewer calories are available to the body. This may help in controlling weight. The main side effects of Xenical are cramping, diarrhea, flatulence, intestinal discomfort, and leakage of oily stool.
Meridia (sibutramine), approved by the FDA in 1997, increases the levels of certain brain chemicals that help reduce appetite. Because it may increase blood pressure and heart rate, Meridia should not be used by people with uncontrolled high blood pressure, a history of heart disease, congestive heart failure, irregular heartbeat, or stroke. Other common side effects of Meridia include headache, dry mouth, constipation and insomnia.
Other anti-obesity prescription drugs that were approved by the FDA many years ago based on very short-term, limited data include: Bontril (phendimetrazine tartrate), Desoxyn (methamphetamine) and Ionamin and Adipex-P (phentermine). They are "speed"-like drugs that should not be used by people with heart disease, high blood pressure, an overactive thyroid gland, or glaucoma. These drugs are approved only for short-term use, such as a few weeks. They generally don't cause weight loss beyond several weeks, and they have significant potential for physical dependence or addiction.
"There is no magic pill for obesity," says David Orloff, M.D., director of the FDA's Division of Metabolic and Endocrine Drug Products. "The best effect you're going to get is with a concerted long-term regimen of diet and exercise. If you choose to take a drug along with this effort, it may provide additional help."
Until September 1997, two other drugs, fenfluramine (Pondimin and others) and dexfenfluramine (Redux), were available for treating obesity. But at the FDA's request, the manufacturers of these drugs voluntarily withdrew them from the market after newer findings suggested that they were the likely cause of heart valve problems. The FDA recommended that people taking the drugs stop and that they contact their doctor to discuss their treatment. (For the latest information on this topic, visit www.fda.gov/cder/news/feninfo.htm.)
Prescription weight-loss drugs are approved only for those with a BMI of 30 and above, or 27 and above if they have other risk factors, such as high blood pressure or diabetes.
People should contact a doctor before using any kind of drug, including a weight-loss drug.
Over-the-counter (OTC) weight-control drugs contain the active ingredient phenylpropanolamine, which is also used as a nasal decongestant. The FDA recently asked drug manufacturers to discontinue marketing products containing phenylpropanolamine, based on evidence linking the substance to an increased risk of hemorrhagic stroke (bleeding in the brain). In addition, the FDA issued a public health advisory in November 2000, warning consumers to stop using products containing this ingredient.
The FDA is proposing to classify phenylpropanolamine as "not generally recognized as safe," and is proceeding with regulatory actions that will likely remove this ingredient from the market.
Beware of Unproven Claims
Some dietary supplement makers claim their products work for weight loss. These products are not reviewed by the FDA before they are marketed. "Under our existing laws, manufacturers have the responsibility for ensuring that their dietary supplement products are safe and effective," says Christine Lewis Taylor, Ph.D., R.D., director of the FDA's Office of Nutritional Products, Labeling, and Dietary Supplements.
Many weight-loss products claim to be "natural" or "herbal," but this does not necessarily mean that they're safe. These ingredients may interact with drugs or may be dangerous for people with certain medical conditions. If you are unsure about a product's claims or the safety of any weight-loss product, check with your doctor before using it.
Worth the Effort
"Losing weight requires major lifestyle changes, including diet and nutrition, exercise, behavior modification, and--when appropriate--intervention with drug therapy," says Judith S. Stern, Sc.D., professor of nutrition and internal medicine at the University of California, Davis, and vice president of the American Obesity Association. "But it is always worth making the effort to improve your health."
Linda Bren is a staff writer for FDA Consumer.
Avoid 'Fad' Diets
The cabbage soup diet, the low-carbohydrate and high-protein diet, and other so-called "fad" diets are fundamentally different from federal nutrition dietary guidelines and are not recommended for losing weight.
Fad diets usually overemphasize one particular food or type of food, contradicting the guidelines for good nutrition, which recommend eating a variety of foods from the Food Guide Pyramid. These diets may work at first because they cut calories, but they rarely have a permanent effect.
A high-protein diet is one fad diet that has remained popular over the years. "High-protein items may also be high in fat," says Robert Eckel, M.D., professor of medicine at the University of Colorado Health Sciences Center in Denver. High-fat diets can raise blood cholesterol levels, which increases a person's risk for heart disease and certain cancers.
High-protein diets force the kidneys to try to get rid of the excess waste products of protein and fat, called ketones. A buildup of ketones in the blood (called ketosis) can cause the body to produce high levels of uric acid, which is a risk factor for gout (a painful swelling of the joints) and kidney stones. Ketosis can be especially risky for people with diabetes because it can speed the progression of diabetic renal disease, says Eckel.
"It's important for the public to understand that no scientific evidence supports the claim that high-protein diets enable people to maintain their initial weight loss," says Eckel. "In general, quick weight-loss diets don't work for most people."
Tips for Eating Out
For More Information
Weight-control Information Network
Obesity Education Initiative
The Surgeon General's Call to
Action To Prevent and Decrease Overweight and Obesity, 2001
American Dietetic Association
American Obesity Association
National Weight Control Registry
Publication No. (FDA) 02-1231
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