Exercise without losing weight

Most of us think we need to lose some weight, so we resolve to eat better and get more exercise. Often, though, that resolve vanishes before the pounds do. Heavy with resignation and body weight, we move on.

But Canadian researchers have reported study results that may mean all is not lost, even if the extra pounds are not.

Their small study included 24 middle-aged men who weren't in the habit of exercising. Eight were lean, eight obese, and eight others obese with type 2 diabetes. For three months, they followed a fairly rigorous exercise program that consisted of an hour of aerobic exercise (activity that increases your heart rate and makes you breathe hard) five times a week.

The twist was that they were told to eat enough to compensate for the extra calories they were burning so they would not lose weight. Outside of a study, many of us don't need to be told to do that. We chow down because exercise stimulates our appetites, and perhaps we figure that the added physical activity gives us some calorie credits we can safely use up.
The researchers made several measurements at the end of three months, but two stood out. In all three groups, the waist size of the men shrank by about an inch, and levels of interleukin-6 (an inflammatory chemical produced by fat and certain other tissues) declined. These and other results were published in the March 2007 issue of the journal Metabolism.

The main reason being overweight is bad for us is that fat tissue is metabolically active, producing hormones and chemicals that harm the cardiovascular and other systems. Fat tissue that accumulates in the midsection - the very stuff that expands our waistlines - is especially active. So it's meaningful that this study showed that exercise, even without weight loss, reduced both waist size (which serves as an easy-to-measure proxy for abdominal fat) and one of the chemicals produced by fat tissue. Still, this was a rather small, short study - an appetizer meant to whet the appetite for more research, not a full-course meal of proof.

Hardly a day goes by without some new finding about the benefits of keeping active. And there's really not much question that exercise that brings about some weight loss is better for us than exercise that doesn't. A number of studies have found that several inflammatory factors decline — not just one — when people exercSise and lose weight.

But this study and many others underscore that regular exercise, even when you don't lose weight, has health benefits. We're making a big mistake if we use weight loss as the only way to measure our exercise efforts. We're making an even bigger mistake if by doing so, we become more easily discouraged, and give up on staying fit and active.

November 2007 update

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