For adults and children, different methods are used to find out if weight is about right for height. If you have concerns about your child’s body size, talk with your health care provider. Also see the section Encourage healthy weight in children. If you are an adult, follow the directions in INDEX to evaluate your weight in relation to your height, or Body Mass Index (BMI).
Not all adults who have a BMI in the range labeled “healthy” are at their most healthy weight. For example, some may have lots of fat and little muscle. A BMI above the healthy range is less healthy for most people; but it may be fine if you have lots of muscle and little fat. The further your BMI is above the healthy range, the higher your weight-related risk. If your BMI is above the healthy range, you may benefit from weight loss; especially if you have other health risk factors (see INDEX 2).
BMI’s slightly below the healthy range may still be healthy unless they result from illness. If your BMI is below the healthy range, you may have increased risk of menstrual irregularity, infertility, and osteoporosis. If you lose weight suddenly or for unknown reasons, see a health care provider. Unexplained weight loss may be an early clue to a health problem.
Keep track of your weight and your waist measurement, and take action if either of them increases. If your BMI is greater than 25, or even if it is in the “healthy” range, at least try to avoid further weight gain. If your waist measurement increases, you are probably gaining fat. If so, take steps to eat fewer calories and become more active.