For Immediate Release: October 15, 2009
NN: Reality Check on Exercise and Weight
Week of November 16, 2009
Contact: Alice Bender, (202) 328-7744
Reality Check on Exercise and Weight
Karen Collins, MS, RD, CDN
American Institute for Cancer Research
A major news magazine’s cover story sent out ripples of shock waves when it suggested that exercise, although good for you, may not make you lose weight. Actually, research shows that if you burn more calories without increasing calories from food and drink, you will lose weight. However, research also shows that exercise does not always predict weight change. The bottom line is that many of us overestimate the impact of how many calories we burn in the exercise we do and don’t account for the extra calories we consume. Most people need changes in eating habits and increased physical activity to lose weight, not one or the other.
Recommendations for overall health, including reduced risk of heart disease and cancer, call for at least thirty minutes of brisk walking or other brisk exercise daily or nearly daily. A 150-pound adult who adds that activity daily (and doesn’t cut back on other activity) burns about 120 to 140 extra calories per day. With no changes in diet, that should lead to weight loss of one pound in 25 to 30 days. On the other hand, if the new walker rewards that walk with an extra muffin, 24-ounce soda or second helping at dinner, after 25 to 30 days his or her weight would probably be a pound higher, not lower. That’s because the increased calories from any one of those are more than double the calories burned in the walk.
Exercise does burn calories faster in some people than others. A 150-pound adult taking a 30-minute brisk walk may burn 140 calories, while someone who weighs 200 pounds burns about 180 calories. And while even modest exercise burns calories in someone who’s been sedentary, activity becomes easier as you increase fitness and burns fewer calories unless you step up the action.
If, like most U.S. adults, you’ve been gradually gaining weight, adding 30 minutes of moderate exercise each day will likely stop the gain, the first priority. If you can be patient, it could even bring weight loss of 10 or more pounds after a year. Weight loss closer to a pound each week from exercise alone would require boosting time, intensity or both to levels unrealistic for most people. Modest changes in daily eating habits can add up more quickly.
Claims that exercise increases appetite and makes it more difficult to limit calorie consumption are not supported by the overall body of research in this field. In fact, several studies show that exercise seems to improve appetite control and make hunger more closely match actual calorie needs. Further research is needed, but studies suggest that exercise delivers this benefit by triggering changes in satiety hormones.
Realistically, weight control expectations shouldn’t be centered on exercise alone. In five minutes or less of unhealthy eating you can replace the calories it took you thirty minutes or more to burn in exercise. The key is to make physical activity, whether in a single block or spread throughout each day, an enjoyment rather than a punishment that earns a reward. Remind yourself of the reality that regardless of any impact on weight, physical activity plays a key role in improving sleep, relieving stress, maintaining cognitive function, and decreasing risk of heart disease, diabetes and cancer.
This is another example of how an overall healthy lifestyle works better than picking just one or two elements of it. If you’re not properly fueled for physical activity, exhaustive exercise could bring a blood sugar drop that leaves you searching for a jelly doughnut or candy bar. But if you provide your body with a balanced plant-based diet including vegetables, fruit, whole grains and adequate protein foods, research does not show that you will overeat just because you’ve made time for the 30 to 60 minutes of moderate physical activity your body needs.