Hate your weight? Your genes may be partly to blame. By determining your body composition, appetite regulation, metabolism and other factors, genes may account for as much as 60 to 70 percent of obesity, some researchers say.

These genes react to environmental conditions, so you can blame those too — sprawling communities that require us to drive everywhere; office jobs that force us to sit all day; leisure activities like TV, movies and chatting online, designed for vegging out.

But no matter what got you to that number on the scale, those 40, 80 or 200 extra pounds are yours to lose. And moving your body is key to doing it. Not only does physical activity burn calories, which helps you shed pounds and keep them off — it also increases energy and lowers the risk of obesity-related diseases, including heart disease, high blood pressure, stroke and type 2 diabetes.

Defy Your Weight Fate
A University of Maryland study showed that people were able to overcome a strong genetic predisposition to obesity by engaging in a substantial amount of physical activity, the equivalent of about three to four hours of moderate exercise daily.

And studies of the National Weight Control Registry, a database of more than 5,000 people who have lost a lot of weight and kept it off, have found that a secret to their success is 60 minutes of exercise a day.

STUDY: Obesity Spreads in Social Networks

Try This

E-mail yourself a reminder to exercise. A study published in June 2009 in the American Journal of Preventive Medicine found that people who received a simple weekly e-mail reminder to get more exercise increased their physical activity by an hour a week.

Life on the Move
If reading those numbers is the only thing that’s gotten your heart rate up all week, you’re not alone. Almost 60 percent of U.S. adults get no vigorous physical activity in their leisure time.

Start by slowly replacing sedentary activities with more active ones — for instance, cut out one TV show a day and spend that half hour taking a walk. Look for ways to make your daily routines just a little more physically demanding.

QUIZ: How Physically Active Are You?

“Let’s say you work on the seventh floor: Take the stairs up one or two flights, whatever is realistic for you, and then take the elevator the rest of the way,’’ suggests Gordon Blackburn, PhD, director of the Cardiac Rehabilitation Program at the Cleveland Clinic. “Or put your garbage can on the other side of your room so you have to get up out of your chair to throw something away.” All these little things add up at the end of the day to calories expended. The bottom line: Get more active. 

If you’ve heard this advice before, that’s because it works. Even if you change nothing else, walking an extra 30 minutes a day can lead to a 10-pound weight loss in a year. And once you start walking, other changes may follow effortlessly. A California State University Long Beach study showed that when frequent snackers who craved a sugary treat went for a brisk five-minute walk instead, they felt less of an urge to eat and waited twice as long before reaching for the next snack. (See how other daily activities can translate into pounds lost per year.)

Workouts That Work
For exercise to work, it needs to be something you’ll actually do, so find an activity you enjoy. That may be riding a stationary bike while watching “American Idol,” or taking a dance class at the local Y. If you feel too self-conscious to go to a gym, you can pop in an exercise DVD at home or try an exercise show on television. Or stick with walking, gradually increasing your pace and distance.

If exercise is painful to your joints or difficult due to extreme excess weight, water workouts or a water aerobics class may be your best starting point. Water’s buoyant effect relieves the strain on joints and makes it easier to move.

Whatever activity you choose, start with 10 minutes three days a week. Gradually build up the duration, frequency and intensity. To lose weight, aim for 60 minutes of moderate to vigorous physical activity most days. Once you reach your goal weight, you’ll need to work a little harder to stay there. Aim for 60 to 90 minutes of moderate to vigorous activity five or more days a week.

You Snooze, You May Lose…Pounds
Studies show that people who sleep five hours a night are much more likely to be overweight or obese than people who get seven to eight hours of shut-eye. Sleep deprivation interferes with the appetite-regulating hormones ghrelin and leptin, causing us to eat more, particularly foods high in carbohydrates and fat.

For a good night’s sleep, set a regular bedtime, drink warm low-fat milk or caffeine-free herbal tea before bed, and move your alarm clock so you don’t lie there staring at the time.

QUIZ: Do You Have Healthy Sleeping Habits?

by Katherine E. Solem