I'm always much more physically active in the summer, but this year I'm also watching what I eat. How can I tell how many calories I'm burning?
You're not alone. Most people are more likely to get out and move in the summer -- why not, with warmer weather and longer hours of daylight?
That said, how many calories you're burning depends on a number of things. The major factor is body size: Larger bodies require more calories for any sort of activity than smaller bodies. So, a 220-pound person will burn more calories doing the same thing as a 120-pound person.
How much of an effort you're putting in also makes a difference. More strenuous activity burns more calories than less-demanding movement.
You can get estimates of how many calories you're burning by doing different activities by entering your weight into various online calculators. But estimating calorie expenditures solely on body size is far from an exact science. If you try six different calculators, you're likely to come up with six different estimates on how many calories you're burning for the same activity.
The problem is that accurate measurements require a lot more information. Much of your calorie burning depends on your basal metabolic rate -- how many calories you burn at rest. And that depends on a lot of things: your age (younger people tend to burn more calories than older folks); your sex (men tend to burn more calories than women); your overall, everyday activity level (the more active you are, the more calories your body burns); your proportion of muscle mass to fat (the more lean tissue you have, the more calories you burn).
Still, no matter what, the more you move, the more calories you will burn. And, if you exercise regularly, your basal metabolic rate will increase over time.
The U.S. Department of Agriculture's "MyPyramid" food guidance system includes physical activity as a staple, along with fruits, vegetables and all the other components of a healthful diet. The basic guidelines are to do moderately intense activity -- walking briskly, doing yard work, or doing some light weight lifting, for example -- for at least 30 minutes most days of the week, if not every day. But even more, up to 60 minutes, may be needed to prevent weight gain. And if you've lost weight, up to 90 minutes a day may be needed to keep it off. All of these activities should be over and above your normal routine, but you can break them up into smaller 10 to 15 minutes chunks if that makes more sense for your schedule. See http://mypyramid.gov for details.
Chow Line is a service of Ohio State University Extension and the Ohio Agricultural Research and Development Center. Send questions to Chow Line, c/o Martha Filipic, 2021 Coffey Road, Columbus, OH, 43210-1044, or filipic.3@cfaes.osu.edu.
Editor: This column was reviewed by Lydia Medeiros, associate professor of human nutrition in the College of Education and Human Ecology, a state specialist with Ohio State University Extension, and a researcher with the Ohio Agricultural Research and Development Center.