weight loss

When it comes to nutrition, it's easy to spend a lot of time worrying about what to eat. But how much you eat puts an even greater stamp on your long-term health than picking the right kind of fats or choosing exactly the right mix of vitamins.

How much you weigh (in relation to your height), your waist size, and how much weight you've gained since your mid-20s strongly influence your chances of:

Despite the substantial impact of weight on individual health, and the soaring rates of obesity in the United States, relatively few Americans see excess weight as a problem. In a survey conducted by researchers at Harvard's Kennedy School of Government, almost 1,000 Americans ranked obesity low on the list of serious health problems. Equally alarming, only 9 percent said their weight was a problem, even though more than half were overweight. That's a shocking finding, given that excess weight leads to at least 300,000 deaths per year and costs more than $70 billion each year in direct costs alone. Obesity now accounts for more deaths and chronic disorders, and poorer health-related quality of life, than either smoking or problem drinking.

If your weight is in the healthy range and isn't more than 10 pounds over what you weighed when you turned 21, great. Keeping it there-and keeping it steady-by watching what you eat and exercising will limit your risk of developing one or more of these chronic conditions noted above. If you are overweight, doing whatever you can to prevent gaining more weight is a critical first step. Then, when you're ready, shedding some pounds and keeping them off will be important steps to better health.

If every picture tells a story, then the one below tells a chilling tale about an epidemic of obesity that poses a major public health problem. In 1991, obese adults made up less than 15 percent of the population in most U.S. states. Ten years later, only one state could claim that distinction. During this span, the Centers for Disease Control and Prevention's annual Behavioral Risk Factor Surveillance System recorded a 61 percent increase in obesity. Today, an estimated 108 million adult Americans weigh more than is healthy.

Even more alarming, the prevalence of overweight and obesity in children and adolescents is on the rise, and children are becoming overweight and obese at earlier ages. An estimated 13-14 percent of children aged 6 to 19 years are considered overweight or obese. Early obesity not only increases the likelihood of adult obesity, and it also increases the prevalence of weight-related risk factors for cardiovascular disease such as hypertension, elevated serum cholesterol, and insulin resistance. Overweight is at least partly responsible for the dramatic increase in diagnoses of type 2 diabetes mellitus (formerly called adult-onset diabetes) among children. In some parts of the United States., more than 30 percent of new cases of type 2 diabetes mellitus are in children, and most of these are attributable to obesity.(13, 14)

Although nutrition experts still debate the precise limits of what constitutes a healthy weight, there's a good working definition based on the ratio of weight to height. This ratio, called the body mass index (or BMI for short), takes into account the fact that taller people have more tissue than shorter people, and so tend to weigh more.

Dozens of studies that have included more than a million adults have shown that a body mass index above 25 increases the

chances of dying early, mainly from heart disease or cancer, and that a body mass index above 30 dramatically increases the chances. Based on this consistent body of research,

a healthy weight is one that equates with a body mass index less than 25. By convention, overweight is defined as a body mass index of 25 to 29.9, and obesity is defined as a body mass index of 30 or higher.

Nothing magical happens when you cross from 24.9 to 25 or from 29.9 to 30. These are just convenient reference points. Instead, the chances of developing a weight-related health problems increases across the range of weights

Muscle and bone are more dense than fat, so an athlete or muscular person may have a high body mass index, but not be fat. It's this very thing that makes weight gain during adulthood such an important determinant of weight-related health--few adults add muscle and bone after their early twenties, so nearly all that added weight is fat.

Calculate your BMI

With a calculator handy (or pencil and paper if you like multiplication and long division), you can determine your body-mass index like this: Divide your weight in pounds by your height in inches. Divide the answer by your height in inches. Multiply the answer by 703.

For a person who is 5'8" (68 inches) and weighs 172 pounds, that would be 172÷68÷68x703, or a shade over 26.

For an easier way, click here and fill in your weight and height.

Aim for a healthy weight

Choose a lifestyle that combines sensible eating with regular physical activity. To be at their best, adults need to avoid gaining weight, and many need to lose weight. Being overweight or obese increases your risk for high blood pressure, high blood cholesterol, heart disease, stroke, diabetes, certain types of cancer, arthritis, and breathing problems. A healthy weight is key to a long, healthy life.

Evaluate your body weight

For adults and children, different methods are used to find out if weight is about right for height. If you have concerns about your child's body size, talk with your health care provider. Also see the section Encourage healthy weight in children.

If you are an adult, follow the directions in box 1 to evaluate your weight in relation to your height, or Body Mass Index (BMI). Not all adults who have a BMI in the range labeled "healthy" are at their most healthy weight. For example, some may have lots of fat and little muscle. A BMI above the healthy range is less healthy for most people; but it may be fine if you have lots of muscle and little fat. The further your BMI is above the healthy range, the higher your weight-related risk. If your BMI is above the healthy range, you may benefit from weight loss, especially if you have other health risk factors (see box 2).

BMI's slightly below the healthy range may still be healthy unless they result from illness. If your BMI is below the healthy range, you may have increased risk of menstrual irregularity, infertility, and osteoporosis. If you lose weight suddenly or for unknown reasons, see a health care provider. Unexplained weight loss may be an early clue to a health problem.

Keep track of your weight and your waist measurement, and take action if either of them increases. If your BMI is greater than 25, or even if it is in the "healthy" range, at least try to avoid further weight gain. If your waist measurement increases, you are probably gaining fat. If so, take steps to eat fewer calories and become more active.

Box 1

HOW TO EVALUATE YOUR WEIGHT (ADULTS)

Weigh yourself and have your height measured.

Find your BMI category in figure 1. The higher your BMI category, the greater the risk for health problems.
Measure around your waist, just above your hip bones, while standing. Health risks increase as waist measurement increases, particularly if waist is greater than 35 inches for women or 40 inches for men. Excess abdominal fat may place you at greater risk of health problems, even if your BMI is about right.
Use box 2 to find out how many other risk factors you have.

The higher your BMI and waist measurement, and the more risk factors you have from box 2, the more you are likely to benefit from weight loss.

NOTE: Weight loss is usually not advisable for pregnant women.

Figure 1

BMI measures weight in relation to height. The BMI ranges shown above are for adults. They are not exact ranges of healthy and unhealthy weights. However, they show that health risk increases at higher levels of overweight and obesity. Even within the healthy BMI range, weight gains can carry health risks for adults.

Directions: Find your weight on the bottom of the graph. Go straight up from that point until you come to the line that matches your height. Then look to find your weight group.

	Healthy Weight BMI from 18.5 up to 25 refers to a healthy weight.
	Overweight BMI from 25 up to 30 refers to overweight.
	Obese BMI 30 or higher refers to obesity. Obese persons are also overweight.

Source: Report of the Dietary Guidelines Advisory Committee on the Dietary Guidelines for Americans, 2000, page 3.

Box 2

FIND OUT YOUR OTHER RISK FACTORS FOR CHRONIC DISEASE

The more of these risk factors you have, the more you are likely to benefit from weight loss if you are overweight or obese.

Do you have a personal or family history of heart disease?
Are you a male older than 45 years or a postmenopausal female?
Do you smoke cigarettes?
Do you have a sedentary lifestyle?

Has your doctor told you that you have

–	high blood pressure?
–	abnormal blood lipids (high LDL cholesterol, low HDL cholesterol, high triglycerides)?
–	diabetes?

Manage your weight

Our genes affect our tendency to gain weight. A tendency to gain weight is increased when food is plentiful and when we use equipment and vehicles to save time and energy. However, it is possible to manage your weight through balancing the calories you eat with your physical activity choices.

To make it easier to manage your weight, make long-term changes in your eating behavior and physical activity. To do this, build a healthy base and make sensible choices. Choose a healthful assortment of foods that includes vegetables, fruits, grains (especially whole grains), skim milk, and fish, lean meat, poultry, or beans. Choose foods that are low in fat and added sugars most of the time.

Try to be more active throughout the day. The physical activity guideline recommends that all adults get at least 30 minutes of moderate physical activity most or preferably all days of the week. To maintain a healthy weight after weight loss, adults will likely need to do more than 30 minutes of moderate physical activity daily. Over time, even a small decrease in calories eaten and a small increase in physical activity can keep you from gaining weight or help you lose weight.

Box 3

CHOOSE SENSIBLE PORTION SIZES

Control portion size. See guideline "Let the Pyramid guide your food choices" for sensible sizes and numbers of servings.

If you're eating out, choose small portion sizes, share an entree with a friend, or take part of the food home (if you can chill it right away).
Check product labels to learn how much food is considered to be a serving, and how many calories, grams of fat, and so forth are in the food. Many items sold as single portions actually provide 2 servings or more. Examples include a 20-ounce container of soft drink, a 12-ounce steak, a 3-ounce bag of chips, and a large bagel.
Be especially careful to limit portion size of foods high in calories, such as cookies, cakes, other sweets, French fries, and fats, oils, and spreads.

The carbohydrates, fats, and proteins in food supply energy, which is measured in calories. High-fat foods contain more calories than the same amount of other foods, so they can make it difficult for you to avoid excess calories. However, low fat doesn't always mean low calorie. Sometimes extra sugars are added to low-fat muffins or desserts, for example, and they may be just as high in calories.

Your pattern of eating may be important. Snacks and meals eaten away from home provide a large part of daily calories for many people. Choose them wisely. Try fruits, vegetables, whole grain foods, or a cup of low-fat milk or yogurt for a snack. When eating out, choose small portions of foods. If you choose fish, poultry, or lean meat, ask that it be grilled rather than fried.

Like younger adults, overweight and obese older adults may improve their health by losing weight. The guidance of a health care provider is recommended, especially for obese children and older adults. Since older people tend to lose muscle mass, regular physical activity is a valuable part of a weight-loss plan. Building or maintaining muscle helps keep older adults active and reduces their risk of falls and fractures. Staying active throughout your adult years helps maintain muscle mass and bone strength for your later years.

If you need to lose weight, do so gradually

If you are overweight, loss of 5 to 15 percent of your body weight may improve your health, ability to function, and quality of life. Aim to lose about 10 percent of your weight over about 6 months. This would be 20 pounds of weight loss for someone who weighs 200 pounds. Loss of 1/2 to 2 pounds per week is usually safe. Even if you have regained weight in the past, it's worthwhile to try again.

Encourage healthy weight in children

Children need enough food for proper growth, but too many calories and too little physical activity lead to overweight. The number of overweight U.S. children has risen dramatically in recent years. Encourage healthy weight by offering children grain products; vegetables and fruits; low-fat dairy products; and beans, lean meat, poultry, fish, or nuts—and let them see you enjoy eating the same foods. Let the child decide how much of these foods to eat. Offer only small amounts of food high in fat or added sugars. Encourage children to take part in vigorous activities (and join them whenever possible). Limit the time they spend in sedentary activities like watching television or playing computer or video games.

Help children to develop healthy eating habits. Make small changes. For example, serve low-fat milk rather than whole milk and offer one cookie instead of two. Since children still need to grow, weight loss is not recommended unless guided by a health care provider.

Serious eating disorders

Frequent binge eating, with or without periods of food restriction, may be a sign of a serious eating disorder. Other signs of eating disorders include preoccupation with body weight or food (or both—regardless of body weight), dramatic weight loss, excessive exercise, self-induced vomiting, and the abuse of laxatives. Seek help from a health care provider if any of these apply to you, a family member, or a friend.

ADVICE FOR TODAY

	Aim for a healthy weight. If you are at a healthy weight, aim to avoid weight gain. If you are already overweight, first aim to prevent further weight gain, and then lose weight to improve your health.
	Build a healthy base by eating vegetables, fruits, and grains (especially whole grains) with little added fat or sugar.
	Select sensible portion sizes.
	Get moving. Get regular physical activity to balance calories from the foods you eat.
	Set a good example for children by practicing healthy eating habits and enjoying regular physical activities together.
	Keep in mind that even though heredity and the environment are important influences, your behaviors help determine your body weight.

Be physically active each day

Being physically active and maintaining a healthy weight are both needed for good health, but they benefit health in different ways. Children, teens, adults, and the elderly—all can improve their health and well-being and have fun by including moderate amounts of physical activity in their daily lives. Physical activity involves moving the body. A moderate physical activity is any activity that requires about as much energy as walking 2 miles in 30 minutes.

Aim to accumulate at least 30 minutes (adults) or 60 minutes (children) of moderate physical activity most days of the week, preferably daily. If you already get 30 minutes of physical activity daily, you can gain even more health benefits by increasing the amount of time that you are physically active or by taking part in more vigorous activities. No matter what activity you choose, you can do it all at once, or spread it out over two or three times during the day.

Make physical activity a regular part of your routine

Choose activities that you enjoy and that you can do regularly (see box 4). Some people prefer activities that fit into their daily routine, like gardening or taking extra trips up and down stairs. Others prefer a regular exercise program, such as a physical activity program at their worksite. Some do both. The important thing is to be physically active every day.

Most adults do not need to see their health care provider before starting to become more physically active. However, if you are planning to start a vigorous activity plan and have one or more of the conditions below, consult your health care provider:

	Chronic health problem such as heart disease, hypertension, diabetes, osteoporosis, or obesity.
	High risk for heart disease (see box 2).
	Over age 40 for men or 50 for women.

Health benefits of physical activity

Compared with being very sedentary, being physically active for at least 30 minutes on most days of the week reduces the risk of developing or dying of heart disease. It has other health benefits as well (see box 5). No one is too young or too old to enjoy the benefits of regular physical activity.

Two types of physical activity are especially beneficial:

	Aerobic activities. These are activities that speed your heart rate and breathing. They help cardiovascular fitness.
	Activities for strength and flexibility. Developing strength may help build and maintain your bones. Carrying groceries and lifting weights are two strength-building activities. Gentle stretching, dancing, or yoga can increase flexibility.

To get these health benefits, adults need moderate physical activity for a total of at least 30 minutes most days of the week, preferably daily, and children need at least 60 minutes per day.

Box 4

EXAMPLES OF PHYSICAL ACTIVITIES FOR ADULTS

For at least 30 minutes most days of the week, preferably daily, do any one of the activities listed below—or combine activities. Look for additional opportunities among other activities that you enjoy.

As part of your routine activities:

Walk, wheel, or bike ride more, drive less.
Walk up stairs instead of taking an elevator.
Get off the bus a few stops early and walk or wheel the remaining distance.
Mow the lawn with a push mower.
Rake leaves.
Garden.
Push a stroller.
Clean the house.
Do exercises or pedal a stationary bike while watching television.
Play actively with children.
Take a brisk 10-minute walk or wheel in the morning, at lunch, and after dinner.

As part of your exercise or recreational routine:

Walk, wheel, or jog.
Bicycle or use an arm pedal bicycle.
Swim or do water aerobics.
Play racket or wheelchair sports.
Golf (pull cart or carry clubs).
Canoe.
Cross-country ski.
Play basketball.
Dance.
Take part in an exercise program at work, home, school, or gym.

Box 5

HEALTH BENEFITS OF REGULAR PHYSICAL ACTIVITY

Increases physical fitness.
Helps build and maintain healthy bones, muscles, and joints.
Builds endurance and muscular strength.
Helps manage weight.
Lowers risk factors for cardiovascular disease, colon cancer, and type 2 diabetes.
Helps control blood pressure.
Promotes psychological well-being and self-esteem.
Reduces feelings of depression and anxiety.

Physical activity and nutrition

Physical activity and nutrition work together for better health. For example, physical activity increases the amount of calories you use. For those who have intentionally lost weight, being active makes it easier to maintain the weight loss. However, 30 minutes of activity daily may not be enough to lose weight or maintain weight loss.

Physical activity and nutrition work together in more ways than weight management. Increasing the calories you use allows you to eat more, which makes it easier to get the nutrients you need. Physical activity and nutrition work together for bone health, too. Calcium and other nutrients are needed to build and maintain strong bones, but physical activity is needed as well.

Help children be physically active

Children and adolescents benefit from physical activity in many ways. They need at least 60 minutes of physical activity daily (see box 6). Parents can help:

	Set a good example. For example, arrange active family events in which everyone takes part. Join your children in physical activities.
	Encourage your children to be physically active at home, at school, and with friends by jumping rope, playing tag, riding a bike.
	Limit television watching, computer games, and other inactive forms of play by alternating with periods of physical activity.

Box 6

PHYSICAL ACTIVITIES FOR CHILDREN AND TEENS

Aim for at least 60 minutes total per day:

Be spontaneously active.
Play tag.
Jump rope.
Ride a bicycle or tricycle.
Walk, wheel, skip, or run.
Play actively during school recess.
Roller skate or in-line skate.
Take part in physical education activity classes during school.
Join after-school or community physical activity programs.
Dance.

Older people need to be physically active too

Older persons also need to be physically active. Engage in moderate physical activity for at least 30 minutes most days of the week, preferably daily, and taking part in activities to strengthen muscles and to improve flexibility. Staying strong and flexible can reduce your risk of falling and breaking bones, preserve muscle, and improve your ability to live independently. Lifting small weights and carrying groceries are two ways to include strength building into your routine.

ADVICE FOR TODAY

	Engage in at least 30 minutes (adults) or 60 minutes (children) of moderate physical activity most, preferably all, days of the week.
	Become physically active if you are inactive.
	Maintain or increase physical activity if you are already active.
	Stay active throughout your life.
	Help children get at least 60 minutes of physical activity daily.
	Choose physical activities that fit in with your daily routine, or choose recreational or structured exercise programs, or both.
	Consult your health care provider before starting a new vigorous physical activity plan if you have a chronic health problem, or if you are over 40 (men) or 50 (women).

Some research suggests that not all fat is created equal. Fat that accumulates around the waist and chest (what's called abdominal adiposity) may be more dangerous for long-term health than fat that accumulates elsewhere. Some studies suggest that abdominal fat plays a role in the development of high blood pressure, high cholesterol, high blood sugar, and heart disease. It's also possible, of course, that abdominal fat isn't worse than fat around the hips or thighs, but instead is a signal of overall body-fat accumulation that weight alone just doesn't capture.

Measuring your waist is easy, if you know exactly where your waist really is. Wrap a flexible measuring tape around your midsection where the sides of your waist are the narrowest. This is usually even with your navel. Make sure you keep the tape parallel to the floor.
An expert panel convened by the National Institutes of Health concluded that a waist larger than 40 inches for men and 35 inches for women increases the chances of developing heart disease, cancer, or other chronic diseases. Although these are a bit generous they are useful benchmarks.

Waist size is a simple, useful measurement because abdominal muscle can be replaced by fat with age, even though weight may remain the same. So increasing waist size can serve as a warning that you ought to take a look at how much you are eating and exercising.

Middle-aged spread is the source of millions of New Year's resolutions. Gaining weight as you age increases the chances of developing one or more chronic diseases. In the Nurses' Health Study and the Health Professionals Follow-up Study, middle-aged women and men who gained 11 - 22 pounds after age 20 were up to three times more likely to develop heart disease, high blood pressure, type 2 diabetes, and gallstones than those who gained five pounds or fewer. Those who gained more than 22 pounds had even larger risks of developing these diseases.

Relation between body-mass index up to 30 and the relative risk of type 2 diabetes, hypertension, coronary heart disease, and cholelithiasis in the Nurses' Health Study among women initially aged 30 to 55 years followed for up to 18 years and in the Health Professionals Follow-up Study among men initially aged 40 to 65 years followed for up to 10 years.

If you burn as many calories as you take in each day, there's nothing left over for storage in fat cells and weight remains the same. Eat more than you burn, though, and you end up adding fat and pounds.

Many things influence what and when you eat and how many calories you burn. These turn what seems to be a straightforward pathway to excess weight into a complex journey that may start very early in life.

Low-fat diets are routinely promoted as a path to good health. But they haven't fulfilled their promise. One reason is that many people have interpreted the term "low-fat" to mean "it's OK to eat as much low-fat food as you want." For most people, eating less fat has meant eating more carbohydrates. To the body, calories from carbohydrates are just as effective for increasing weight as calories from fat.

In the United States, obesity has become increasingly common even as the percentage of fat in the American diet has declined from 45 percent in the 1960s to about 33 percent today. In South Africa, nearly 60 percent of people are overweight even though the average diet contains about 22 percent of calories from fat. Finally, experimental studies lasting one year or longer have not shown a link between dietary fat and weight.

Another increasingly common approach to weight loss is eating more protein and less carbohydrates. One widely publicized high-protein diet entails loading up on meat, cheese, fish, and eggs while dramatically cutting down or even eliminating carbohydrates. This may help you drop some pounds. But the long-term effects of this eating strategy--on weight as well as overall health--aren't yet clear.

Limiting carbohydrates can help avoid sharp spikes in blood sugar and insulin levels, and equally sharp declines in blood sugar. Keeping blood sugar at a relatively steady level may dampen the appetite. However, many high-protein, low carbohydrate diets are full of saturated and trans fats. These could significantly increase the risk of heart disease regardless of any actual weight loss. A restrictive high-protein, low-carbohydrate diet may also limit the consumption of important vitamins, minerals, and other nutrients found in banned carbohydrates such as fruits, vegetables, and whole grains.

Emerging evidence suggests that a more balanced approach that includes protein, carbohydrates, and fats has value as a weight-loss strategy.

In a study conducted at Duke University, 51 healthy but overweight or obese volunteers were placed on a diet that included no more than 25 grams of carbohydrate a day, but that put no daily limit on calories. They also received counseling and support on nutrition and exercise. After six months, 41 of the volunteers were still following the program. This is a higher percentage than usually seen with people on low-fat diets. Mean body weight decreased 10.3 percent (or approximately 20 pounds) and the mean percentage of body weight that was fat decreased 3 percent. Cholesterol levels improved across the board, with decreases in LDL and triglycerides and increases in HDL.

In such high-protein, low-carbohydrate diets, the types of carbohydrates and fats is probably of critical importance for long-term health. A high-protein diet that emphasizes monounsaturated and polyunsaturated fats while limiting saturated and trans fats will invariably be better than one that includes saturated and trans fats.

Since 1993, nearly 3,000 women and men have joined the National Weight Control Registry. This select "club" includes only people who lost more than 30 pounds and kept them off for at least a year. What was their secret?

Keep in mind that these are commonly used strategies, not hard and fast rules. In fact, one of the main take-home messages is that successful weight loss is very much a "do it your way" endeavor.

These findings are echoed in a survey of more than 32,000 dieters reported in the June 2002 issue of Consumer Reports. Nearly one-quarter had lost at least 10 percent of their starting body weight and kept it off for at least a year. Most chalked up their success to eating less and exercising more. The vast majority did it on their own, without utilizing commercial weight-loss programs or resorting to weight-loss drugs.

Interestingly, the successful losers in the Consumer Reports survey tended to adopt low-carbohydrate/high-protein diets rather than low-fat diets.

What these two groups have in common is a focus on exercise and daily calories. In other words, they've learned to balance energy in and energy out in a way that leads to weight loss or weight maintenance.

So despite all the pessimistic prognostications about the impossibility of sticking with a weight-loss plan, these two surveys show that it's possible to lose weight and keep it off. Unfortunately, only a minority of people who try to lose weight follow the simple, tried-and-true strategy of eating fewer calories and exercising daily. For weight control, an hour of exercise a day may be needed.

It's easy to gain weight in what Yale psychologist Kelly Brownell calls our "toxic food environment." How, then, can you lose weight if you need to? Here are some suggestions that work:

Set a realistic goal. Many people pick weight goals they'll have a hard time achieving, like fitting into a size 8 dress or a wedding tuxedo from 20 years ago. A better initial goal is 5-10 percent of your current weight. This may not put you in league with the "beautiful people" profiled in popular magazines, but it can lead to important improvements in weight-related conditions such as high blood pressure and diabetes. You don't have to stop there, of course. You can keep aiming for another 5-10 percent until you're happy with your weight. By breaking weight loss into more manageable chunks, you'll be more likely to reach your goal.

Slow and steady wins the race. Dieting implies privation and hunger. You don't need either to lose weight if you're willing to take the time to do it right. If you cut out just 100 calories a day, the equivalent of a single can of soda or a bedtime snack, you would weigh 10 pounds less after a year. If, at the same time, you added a brisk 30-minute walk 5 days a week, you could be at least 20 pounds lighter.

Exercise more. The amount of energy the body uses to breathe, pump blood, keep muscles ready for action, and other mundane but vital tasks is called resting metabolism. It accounts for two-thirds of your daily energy expenditure. The more you work your muscles--especially with strength training exercises--the more blood sugar they sponge from the blood and the more calories they burn even when you aren't active. If you don't exercise, try a walking program. Start out with something simple--get off your bus a stop early and walk the rest of the way to work, park your car at the far end of the company or mall parking lot, or take a brisk walk at lunch or when you come home. Gradually increase the amount of time you walk each day until you do 30 or more minutes a day. A pedometer can help you keep track of your daily activity. These watch-like devices hang from a belt and record how many steps you take. A good goal is 10,000 steps a day. If you already exercise, try to increase its intensity or duration.

Keep track. It's easy to eat more than you plan to. A daily food diary can make you more aware of exactly how much you are eating. Include everything, no matter how small or insignificant it seems. Small noshes and drinks of juice add up to real calories.

Tame your blood sugar. Eating foods that make your blood sugar and insulin levels shoot up and then crash may contribute to weight gain. Such foods include white bread, white rice, and other highly processed grain products. As an alternative, choose foods that have a gentler effect on blood sugar (what's called a lower glycemic index). These include whole grains such as wheat berries, steel-cut oats, and whole-grain breads and pasta, as well as beans, nuts, fruits, and vegetables.

Don't be afraid of good fats. Fat in a meal or in snacks such as nuts or corn chips helps you feel full. Good fats such as olive or canola oil can also help improve your cholesterol levels when you eat them in place of saturated or trans fats or highly processed carbohydrates.

Bring on the water. When you are thirsty, reach for water. Drinking juice or sugared soda can give you several hundred calories a day without even realizing it.

The longest journey starts with a single step. Most people don't suddenly decide to lose weight and head straight for their goal. It's a trial and error process. The more you learn and the more support you can get, the more likely you'll be to reach your target.

In our society, food is everywhere--the mall and gas station, the ballpark and drug store. Super size meals in fast food restaurants are almost too good a bargain to pass up, and servings in all but the most trendy restaurants are often enough to feed two. In the face of such plenty, it's important to learn how to avoid overeating. Here are some strategies that help defend against eating too much:

What's sometimes lost in the dire predictions about overweight and obesity in America are the enormous benefits of staying lean or working toward a healthier weight. Maintaining a healthy weight throughout life is associated with lower rates of premature death and heart disease, some cancers, and other chronic conditions. What if you're past that point? Losing 5-10 percent of your weight can substantially improve your immediate health and will decrease your risk of developing such problems. The best time to start losing weight is with the first signs that your weight is straying upward. The more overweight you are, the more difficult it can be to lose weight. But as participants of the National Weight Control Registry have proven, anyone can lose weight.

It's certainly possible to be dangerously thin. Individuals with eating disorders such as anorexia nervosa and bulimia--and those with wasting diseases such as cancer, AIDS, and heart failure--can lose so much weight that they don't have enough energy or basic building blocks to keep themselves alive. What about people who are thin but don't have an eating disorder?

Some studies suggest that the connection between body mass index and premature death follows a U-shaped curve. This would mean that weighing too much--or too little-- isn't as healthy as some middle weight.

The main problem with this idea is that most of these studies included smokers and individuals with early but as-yet undetected chronic and fatal diseases. Cigarette smokers as a group weigh less than nonsmokers, in part because smoking deadens the appetite. Potentially deadly chronic diseases such as cancer, emphysema, kidney failure, and heart failure can cause weight loss even before they cause symptoms and have been diagnosed

So low weights don't necessarily cause early death. Instead, low weight is often the result of illnesses or habits that may be fatal.

One way to untangle this chicken-and-egg problem in epidemiologic studies is to look only at nonsmokers and to ignore deaths in the first few years of follow-up. The most recent such efforts come from two large, long-term studies established by the American Cancer Society. Its first and second Cancer Prevention Studies included more than 1 million adults who were followed for at least 12 years.

They excluded smokers excluding smokers and those with a history of cancer or cardiovascular disease at baseline, or who developed a chronic disease in the first few years of follow-up. Both studies showed a clear pattern of increasing mortality with increasing weight. These data confirm similar observations from a 27-year follow-up of more than 19,000 middle aged men in the Harvard Alumni Study, a 16-year follow-up of 115,000 middle-aged women in the Nurses' Health Study, and a 12-year follow-up of nonsmoking Seventh-day Adventists.

According to the current Dietary Guidelines for Americans a body mass index below 18.5 falls outside the healthy range. But some people manage to live long, healthy lives with a low body mass index. Here's a good rule of thumb: If you've always had a low body mass index and your weight doesn't change, don't worry. But if you start losing weight and aren't dieting or trying to lose weight, schedule a visit with your doctor to figure out why this is happening.