Philip J. Goscienski, M.D.
Is it possible for someone of normal weight to be obese? In a word, yes. It's not weight that determines obesity, but excess fat. The muscles of a person who does not exercise will shrink and may be replaced by fat in and around the remaining muscle fibers. Weight and overall body size may remain the same but the percentage of body fat may be higher than normal.
You may have heard that muscle turns into fat as we get older. Not true. If we become less active we don't need as much muscle, so the body allows it to simply waste away. That same lack of activity, if our calorie intake is the same, causes us to store fat, and much of it accumulates in and around muscle
Another area of hidden fat is within the abdomen. It may not be an obvious pot belly but a large waist means large risk. A man's waist should be no larger than 40 inches, a woman's no larger than 35. A large abdomen is one ingredient of metabolic syndrome, which includes abnormalities of cholesterol and blood sugar, and increases the likelihood of heart attack and stroke.
If nature made it so easy for us to accumulate body fat it must have done so for a good reason. The most obvious purpose is that it allowed early humans to store up reserve energy against hard times and that is probably correct. In some races such as Native Americans that became a liability when they adopted the affluent Western lifestyle. Some tribes in North America have soaring rates of obesity and type 2 diabetes and the complications that accompany both.
Women should not be concerned about the health risks of subcutaneous (under the skin) fat if their percentage of body fat is normal and if they are physically fit. They naturally have more fat than men, and for good reason. A certain level of body fat is necessary for healthy pregnancy and lactation. In fact, female athletes who deliberately lower their body fat to below-normal levels stop menstruating. That's nature's way of saying that they don't have enough long-term energy stores to support a pregnancy.
Fat is not just an inert mass. It actively produces hormones that worsen type 2 diabetes and chemicals that increase inflammation, a factor in causing heart attacks. An excess of abdominal fat, especially in older women, dramatically increases the likelihood of heart disease and stroke.
How can you tell if you have hidden fat? Check your waist size. The risk begins at the figures above, 40 inches for men and 35 inches for women, but the ideal is less, depending on your frame. Measuring your body fat is ideal but underwater weighing (the most reliable) is expensive and caliper measurements can be misleading. Bioimpedance, using a device that resembles a bathroom scale, is fairly accurate if done under standardized conditions.
If you weigh today what you did in high school, congratulations! Especially if you can still fit into the same clothes. If not, it's time to make some lifestyle decisions.
Philip J. Goscienski, M.D. is the author of Health Secrets of the Stone Age, Better Life Publishers 2005. Contact him at firstname.lastname@example.org.