What Is Overweight?
Doctors use the Body Mass Index (BMI) as a convenient method of assessing whether someone is underweight, normal weight or overweight. According to the body mass index, a person is deemed overweight if they have a BMI of 25 or higher. BMI is based on 2 variables, weight and height, but takes no account of body fat percentage. Thus it is less accurate when determining the weight/health status of muscular athletes (who may be classified as mildly or seriously overweight), or older unfit people (who may be classified as normal, even though they may have too high a proportion of body fat). In addition, BMI is a Western system and therefore not entirely appropriate for Eastern peoples, whose body frame may differ. See also: Body Fat/Adipose Tissue – Why We Gain Fat
What Is Severe Overweight
Seriously overweight people – those with a BMI > 30 – are usually classified as “obese”, although obesity is actually a disease of excess fat. The body mass index divides obesity, as follows: mild obesity (BMI 30-34); severe obesity (BMI 35-39); morbid obesity (BMI 40-49); and super-obesity (BMI 50+).
When Does Overweight Affect Health?
The general consensus among doctors is as follows:
- There is no health risk for people of normal weight (BMI 19-24).
- In general, there is little or no risk for people whose excess weight is muscle tissue.
- There is a small but increasing risk of disease for people whose BMI is in the range 25-29, especially if their waist circumference is > 35 (women) or 40 (men).
- The danger of ill-health becomes rapidly more significant for people whose BMI exceeds 30, especially if their waist measurement exceeds the above guidelines.
- Factors which may further aggravate the health dangers of overweight, include: a history of weight-related ill-health, or a lifestyle which includes smoking, heavy drinking or an unbalanced diet.
Exceptions To The Weight/Health Effects
Probably most of us know several people who lived to a ripe old age, despite being very overweight. This does not mean that in general weight doesn’t affect health. On the contrary, statistics show a clear correlation between disease and overweight. Remember, longevity is not just the only indicator of “health”. Time spent suffering from ill-health is another. For example, the average American woman spends 13.5 percent of her life (11 years) in ill-health, while the average American man is sick for about 10.8 percent of his life (8 years). One way to reduce sickness is to maintain a healthy weight.