Because 3,500 calories equals about 1 pound (0.45 kilogram) of fat, you need to burn 3,500 calories more than you take in to lose 1 pound. So if you cut 500 calories from your diet each day, you'd lose about 1 pound a week (500 calories x 7 days = 3,500 calories). Because of changes that occur in the body over time, however, calories may need to be decreased further to continue weight loss.
While diet has a stronger effect on weight loss than exercise does, physical activity has a stronger effect in preventing weight gain and maintaining weight loss.
For most healthy adults, the Department of Health and Human Services recommends these exercise guidelines:
- Aerobic activity. Get at least 150 minutes a week of moderate aerobic activity or 75 minutes a week of vigorous aerobic activity. However, to effectively lose or maintain weight, some people may need up to 300 minutes a week of moderate physical activity. You also can do a combination of moderate and vigorous activity. The guidelines suggest that you spread out this exercise during the course of a week, and sessions of activity should be at least 10 minutes in duration.
- Strength training. Do strength-training exercises at least twice a week. No specific amount of time for each strength-training session is included in the Department of Health and Human Services guidelines, but many suggest that two to three strength-training sessions a week for 20 to 30 minutes are enough for most people.
Moderate aerobic exercise includes such activities as brisk walking, swimming and mowing the lawn. Vigorous aerobic exercise includes such activities as running and aerobic dancing. Strength training can include use of weight machines or performing activities such as rock climbing or heavy gardening.
As a general goal, aim for at least 30 minutes of physical activity every day. Check this chart to find out the estimated number of calories burned while doing various exercises for one hour. Specific calorie expenditures vary widely depending on the exercise, intensity level and your individual situation.