To keep from becoming an obese adult, let your mom know before you're born not to gain too much weight. Expectant mothers who gain too much weight during pregnancy tend to give birth to heavier babies, who are more likely to become obese later in life, according to a study published this week in the Lancet. Those infants may also be more prone to developing asthma, allergies, heart disease, diabetes, and cancer. "Excess weight gain isn't only bad for the mother—it has an adverse effect on unborn fetuses, too," says study coauthor David Ludwig, director of the Optimal Weight for Life program at Children's Hospital Boston. "The nine months before birth are the most important in determining a child's long-term health risks."
Optimal weight gain depends on starting weight, activity level, and metabolism. But the Institute of Medicine, which advises the federal government, recommends maximum weight gain during pregnancy of 25 pounds for women who are already overweight or obese, 35 pounds for women in the normal range, and 40 pounds for those who are underweight. To avoid gaining excess weight when you're expecting, consider these strategies:
Forget about "eating for two." That notion is "inappropriate and needs to be dispelled," says Anna Maria Siega-Riz, a professor of nutrition and an expert in public health at the University of North Carolina-Chapel Hill. From the second trimester on, pregnant women should consume an additional 350 to 450 calories per day; an extra sandwich, glass of milk, and piece of fruit will typically suffice, she says.
Take inventory of your diet. Gaining 10 pounds from junk food, sugary beverages, and too much time on the couch is more detrimental than gaining the same weight from a healthful diet. Eliminate juice, sugared iced tea, and sweetened beverages, and opt instead for water. And make sure you're not eating chips and other snacks that are only empty calories with minimal virtues like vitamins, minerals, and fiber. Load up on vegetables, fruits, whole grains, and healthful fats from foods like olive oil, nuts, and avocados. Those choices are more filling than fried, processed foods, so the same number of calories will go further, Ludwig says.
Pregnancy loves company. Groups for expectant mothers can offer emotional support. "Someone once told me, 'I don't care if this other person is an alien, as long as she's pregnant,'" Siega-Riz says. "If you go for a walk with your husband, you might be five feet behind, huffing and puffing. But if you go for a walk with another pregnant woman, you'll be huffing and puffing together."
Develop a daily exercise routine. For most expectant mothers, physical activity is a must, Siega-Riz says. Walking the dog, running, swimming, or an aerobics class are all good bets. However, pregnant women should avoid activities that could cause blunt injuries, such as bouncing on a trampoline, and scuba diving, which could cause the fetus to develop decompression sickness, or "the bends," a potentially fatal condition resulting from a rapid decrease in pressure when divers ascend too quickly.
To avoid mindless munching, reduce stress. Consider a nature walk or gentle yoga poses to ease stress, or close your eyes and listen to calming music. If you know you cope with stressful situations by indulging in comfort foods, surround yourself with healthful snacks—or at least choose foods that are lower in fat and sugar.
Go digital. iPregnancy, a popular iPhone app, features a tool that helps women determine the optimal number of pounds to gain each week. Women can also record notes and keep a weight-gain journal, which they can E-mail to their doctor. The app, designed by obstetrician-gynecologist Gregory Moore, who practices in Richmond, Va., costs $4.99 on iTunes.