After years of hearing that just about any kind of body fat is bad, we are now learning a more nuanced way of thinking about fat. First of all, a body fat content of zero is unhealthy and actually dangerous. We need a certain amount of fat in our bodies for insulation and fuel reserves; the trick is to maintain that healthy level without going overboard. As we age, that “sweet spot” becomes harder to find and stick to, and the pounds and inches creep on.
As a result, one often hears that complaint that as you get older you have to eat half as much and work out twice as hard to lose weight than when you were younger. New research on the “good” brown fat in our bodies shows why this is the case.
Good Fat, Bad Fat, Brown Fat, White Fat
Recent studies have focused on the discovery that there is “good fat” in our bodies as well as the “bad fat”. This is brown fat, distinguished in both color and function from the white fat that is typical of unhealthy weight gain. Researchers have long known that brown fat works to generate heat, which it does by increasing the metabolism, and that burns off more of the white fat. Babies have stockpiles of brown fat in their bodies to meet their higher need for body heat. It can be found in places where it is not found in adults, such as between the shoulder blades.
The Good News and Bad News about Brown Fat
It was long thought that brown fat disappeared after babyhood but in recent years it has been found that people have brown fat, in lesser amounts, in their bodies throughout life. This fat continues to release chemicals that increase the body’s metabolism and cause it to burn off white fat.
The bad news is, as a new study from Japan’s University of Shizuoka shows, the activity of the brown fat decreases as one gets older. If a person continues to eat and exercise (or not exercise) at the same levels, weight gain starts to pile up. This is the mechanism behind the complaint of one’s “slowing metabolism.”
Behind this bad news, however, are some positive possibilities. Based on research with mice, the Shizuoka researchers believe they have identified the source of the “switch” that causes the brown fat to slow its activity. Future research will begin to focus on ways to keep this switch set to on, or to reactivate it, to help our aging bodies function more efficiently.
In the meantime…
Unfortunately, those methods are not yet available. So we have to continue the middle age battle of the bulge for the time being. With the understanding of how and why the metabolism slows down, it’s easy to see that the best thing to do is try to slow the buildup of the harmful white fat. How to do this? Doctors and nutritionists offer these suggestions:
- After 40, decrease your caloric intake per day by at least 200 calories. If you have been accustomed to overindulgence, you will need to cut back more. (Hint: most 20-oz soda drinks and typical candy bars are between 200 and 250 calories!)
- A diet lower in fat and higher in carbohydrates seems to help slow fat buildup, but it is vital that the carbohydrates come from unprocessed and less-processed food like whole grains, vegetables, and fruits. A diet low in fat but full of “junk” carbs doesn’t do the trick.
- Get a steady amount of moderate exercise. It is not necessary to take up CrossFit or trail running! Doctors say that 30-45 minutes of moderate exercise done 5-6 days a week goes a long way toward maintaining a healthy weight and body fat percentage.