Doctors, dietitians, and others who study weight management don't completely understand what causes the pounds to pile on for some people and not for others. Still, there are quite a few factors that we know make a person more likely to become overweight.
Understanding these risk factors can help you avoid weight gain in the first place, and may alert you to seek treatment for health risks associated with excess weight.
Your age
As you age, your body tends to lose muscle and accumulate fat. But fat needs far fewer calories per pound than muscle does, so your body's need for energy declines with each birthday — to the tune of 2% a decade beginning at age 25. On average, women gain about 16 pounds between ages 25 and 54; for men, the average is 10 pounds between ages 25 and 45.
Fortunately, you can counteract this natural tendency to gain weight. Resistance training (lifting weights) prevents the loss of muscle mass and can even build new muscle at the same time.
Fortunately, you can counteract this natural tendency to gain weight. Resistance training (lifting weights) prevents the loss of muscle mass and can even build new muscle at the same time.
Your genes and family history of obesity
Obesity and a tendency toward being overweight seem to run in families. But scientists still aren't sure just how large a role genetics really plays. Most experts estimate that your family tree accounts for about 25% to 40% of what influences your body type, size, and weight. But studies of identical twins raised in separate households show that heredity might be even more influential when it comes to determining how much weight you'll gain and where it will settle.
Your parents are a strong indicator of your risk for obesity. Among children whose moms and dads both have healthy weights, only 14% become obese. But in families where both parents are obese, nearly 70% of children follow in the footsteps of the adults.
But your heredity needn't be your destiny. Even if your family has a history of weight problems, you can still reach and maintain a healthy weight. Though genes have an influence that can't be avoided, families can also pass on poor eating habits and sedentary lifestyles that can be overcome. And developing and fostering new and healthy family habits will make it easier to maintain a normal weight.
Your parents are a strong indicator of your risk for obesity. Among children whose moms and dads both have healthy weights, only 14% become obese. But in families where both parents are obese, nearly 70% of children follow in the footsteps of the adults.
But your heredity needn't be your destiny. Even if your family has a history of weight problems, you can still reach and maintain a healthy weight. Though genes have an influence that can't be avoided, families can also pass on poor eating habits and sedentary lifestyles that can be overcome. And developing and fostering new and healthy family habits will make it easier to maintain a normal weight.
High-calorie diets
Many people are overweight not only because of what they eat, but also because of how much they eat.
The United States Department of Agriculture's Continuing Survey of Food Intake by Individuals reveals that Americans are indeed avoiding fat — and yet they eat too many and too much of high-calorie foods, including low-fat products.
Between 1991 and 1996, says the survey, the number of calories eaten daily by the average American actually rose nearly 10%. The greatest influence on this trend, the researchers think, is that many Americans have an exaggerated idea of what an adequate serving size is.
Between 1991 and 1996, says the survey, the number of calories eaten daily by the average American actually rose nearly 10%. The greatest influence on this trend, the researchers think, is that many Americans have an exaggerated idea of what an adequate serving size is.
Lack of physical activity
You gain weight when you eat more calories than your body uses. But what you eat is only one side of the equation. The other side is physical activity. Getting enough exercise can help you maintain your current weight — and if you burn up more calories than you eat, you'll tip the scales and lose weight.
But fewer than 40% of American adults are regularly physically active. In fact, a quarter of them get no exercise whatsoever. Part of the explanation can be found in remote controls, washing machines, and self-propelled lawn mowers: Technology has replaced activity in our lives. For example, about 25% of all trips are less than a mile long — yet Americans make about 75% of those trips by car. Each of those trips is an opportunity to burn calories — but three out of four of those opportunities are missed.
Increasing your physical activity doesn't have to be technical. Look at your alternatives each time you turn to a modern convenience — your car, your dishwasher, the escalator at the mall. Running more of your shorter errands on foot, doing more of your household chores by hand, and taking the stairs more often will boost the number of calories you burn each day — and help shift the balance toward weight loss.
But fewer than 40% of American adults are regularly physically active. In fact, a quarter of them get no exercise whatsoever. Part of the explanation can be found in remote controls, washing machines, and self-propelled lawn mowers: Technology has replaced activity in our lives. For example, about 25% of all trips are less than a mile long — yet Americans make about 75% of those trips by car. Each of those trips is an opportunity to burn calories — but three out of four of those opportunities are missed.
Increasing your physical activity doesn't have to be technical. Look at your alternatives each time you turn to a modern convenience — your car, your dishwasher, the escalator at the mall. Running more of your shorter errands on foot, doing more of your household chores by hand, and taking the stairs more often will boost the number of calories you burn each day — and help shift the balance toward weight loss.
Psychological factors
Some of us are emotional eaters: We respond to difficult feelings — sadness, stress, frustration — by overeating. As many as one-third of the obese people seen in clinical settings, and about 5% of the general population overall, may suffer from what's known as binge eating disorder. Like bulimics, people with BED now and then lose control and eat until they are uncomfortably full. But — unlike people with bulimia — binge eaters don't rid (or "purge") their bodies of the extra calories by vomiting, fasting, or taking laxatives. The repeated bouts of overeating eventually lead to weight gain.
Individual counseling and group programs with eating-disorder specialists — such as psychologists, psychiatrists, and specially trained social workers — can help emotional eaters gain control of bingeing and manage their weight.
Individual counseling and group programs with eating-disorder specialists — such as psychologists, psychiatrists, and specially trained social workers — can help emotional eaters gain control of bingeing and manage their weight.
Giving up smoking
Nicotine suppresses your appetite and increases your metabolism. So when you stop smoking, you may gain some weight. If you do, keep in mind that the nicotine you're giving up is a much bigger health hazard than the weight you've gained. The Journal of the American Medical Association, in fact, says there's only one factor that plays a role in more U.S. deaths than obesity: smoking.
Keep an eye on portion sizes, cut back on snacks, and increase how much exercise you get; these steps will help you keep the post-quitting poundage to a minimum. The drug Zyban — sometimes prescribed to help smokers quit — may also help keep them from gaining weight.
Keep an eye on portion sizes, cut back on snacks, and increase how much exercise you get; these steps will help you keep the post-quitting poundage to a minimum. The drug Zyban — sometimes prescribed to help smokers quit — may also help keep them from gaining weight.
Prescription drugs
Some common prescription drugs — such as steroids (prednisone is one) — can cause weight gain. So can many psychiatric drugs, including some antidepressants. If you gain weight as a side effect of a medication, talk to your doctor. He or she may be able to prescribe a different drug, one that will give you the same benefits without adversely affecting your weight.
Childhood obesity
Overweight children are more likely to grow up to become overweight adults. For example, studies suggest 80% of children who are obese between the ages of 10 and 13 will be obese grown-ups. Read about what you can do to prevent or address childhood obesity in Childhood Weight Gain.
Pregnancy weight gain
Some women never lose the weight they gained during pregnancy. About 40% of the women who responded to the 1988 National Maternal Infant Survey were unable to lose at least nine pounds of what they'd gained. Thirty-four percent said they were still carrying at least 14 pounds of leftover "baby fat."
It's normal and healthy to gain weight when pregnant. Every woman is different, of course, but a woman of average weight usually gains between 25 and 35 pounds. Women who are already overweight, though, should gain a little less than that, from 15 to 25 pounds. If you're concerned about weight gain during pregnancy, talk to your obstetrician.
It's normal and healthy to gain weight when pregnant. Every woman is different, of course, but a woman of average weight usually gains between 25 and 35 pounds. Women who are already overweight, though, should gain a little less than that, from 15 to 25 pounds. If you're concerned about weight gain during pregnancy, talk to your obstetrician.
Illnesses and medical conditions
Some illnesses can result in weight gain — especially illnesses related to the thyroid (an organ in the throat that affects metabolism) or to parts of the brain that control appetite. Only about 1% of all cases of obesity are thought to be due to these conditions, which include hypothyroidism, hypopituitarism, and Cushing's syndrome. Although quite rare, damage to the part of the brain called the hypothalamus can also cause weight gain.