If you’re trying to assess your body weight in terms of health, it’s not entirely straightforward. Let’s take a look at some of the more common and lesser known ways to assess a healthy body weight and what some of the limitations are in doing so.
BMI – body mass index can be calculated easily online with your height and weight. A BMI calculator will give a number that fits on the scale range and will classify you as underweight, normal weight, overweight, obese and morbidly obese. This number is supposed to predict your risk of chronic disease. Another option is to calculate your “ideal weight” using what’s called the Hamwi equation (below):
Men: First 5 feet = 106 pounds. For every inch over 5 ft. multiply by 6. Example: 6’2” male = 106 + (12 x 6) = 178 pounds. If larger frame size add 10%; if smaller frame size subtract 10%.
Women: First 5 feet = 100 pounds. For every inch over 5 ft. multiply by 5. Example 5’4” female = 100 + (4 x 5) = 120 pounds. If larger frame size add 10%; if smaller frame size subtract 10%.
What BMI and the Hamwi equation don’t take into account is body composition. Many people whose weight appears healthy but have more muscle mass can often show up as overweight or obese because muscle weighs more than fat. Then you have examples of people who are “skinny fat” – their weight is considered healthy but their body fat is too high. What we know is those with higher than normal body fat percentages (particularly visceral fat in the mid-section) tend to have higher risks for diabetes, some cancers and chronic conditions.
So if we know that body composition – how much fat and muscle we have – is the best predictor for health then why don’t we get rid of scale weight altogether? The main reason is we don’t have a viable way for us at home or in our doctor’s office to easily measure it. You need someone that has good technique with calipers or other measuring devices that can be very expensive. Expensive devices, one being the bod pod, are not thrown off by our level of hydration so they are the most reliable.
Until we have a reliable and easy way to measure body composition ourselves I advise clients to rely on their fitness and health professional with the use of calipers. According to the National Institutes of Health and the World Health Organization a healthy body fat for women is anywhere from 21-36% dependent on age and for men anywhere from 8-25% dependent on age. I suggest having a baseline measurement and then have it re-done in 3 months by the same health professional. Strength training and adequate protein will help you gain muscle; cardio and calorie-reduction will help you lose fat.