So many women are battling to lose weight – yet they keep getting heavier and heavier. Since 1980, the incidence of overweight in American women has jumped by nearly 10 percent, according to the US Department of Health and Human Services. We don’t need government statistics to see the decade-by-decade changes as we get older. One woman in five is overweight in her twenties.
The problem intensifies during the later reproductive years: more than a third of women age 30 to 49 weigh too much. But the numbers really soar at menopause. An astonishing 52 percent of women in their fifties are overweight.
We all know that excess weight endangers health. Overweight triples the normal risk for heart disease and stroke, contributes to diabetes, and has even been linked to cancer. Dr. C. Everett Koop, former US Surgeon General, estimates that 300,000 Americans die from overweight-related causes each year! And millions of heavy women suffer from associated medical conditions that diminish the quality of their lives – from heartburn, to joint pain, to infertility. The burden is emotional as well. Many women are caught in a sad vicious circle: feeling depressed about their weight, seeking consolation in food, gaining more weight, and feeling even worse.
In desperation, some turn to risky medications and fad diets. But it’s actually healthier to remain heavy than to lose weight the wrong way. I’m not just talking about the obvious dangers, like life-threatening side effects from drugs or nutritional deficiencies from unbalanced diets. Even the standard “sensible” advice – to eat 1000 to 1200 calories a day – puts women at risk because they lose so much lean tissue along with fat.
Preserving muscle and bone is vitally important for women. We start out with a lot less muscle and bone than men do, so we have a narrower margin of safety. Yet we live longer, so we’re much more likely to reach an age where our lives are severely limited by muscular weakness or fragile bones.
But there’s a much more immediate reason to be concerned about the loss of lean tissue: The less muscle you have, the harder it is to lose weight and to maintain the loss. Muscle is metabolically active; body fat isn’t. So the smaller the proportion of muscle in your body, the lower your metabolic rate. To make matters worse, when you lose muscle, you become weaker and have less energy. Consequently, you’re likely to burn fewer calories through physical activity. If you’ve ever hit a long plateau during a diet and remained stuck at the same weight despite all your efforts, this could be a reason.
The kind of dieting that leads to muscle loss also sabotages metabolism in another way: by cutting calories too drastically. Nature cleverly designed the human body so we could survive famine. If you put yourself on starvation rations – and for some women even 1200 calories a day is starving – you trigger hormonal shifts that help the body conserve calories instead of burning them. But when you’re trying to lose weight, that’s the last thing you want! Between the starvation effect and muscle loss, the wrong diet can reduce your metabolic rate by up to 30 percent.
These metabolic changes help explain the all-too-common phenomenon of “yo-yo” dieting: A woman manages to lose weight – but in the process, she undermines herself by depressing her metabolism. Maintaining the loss is a losing battle. She’s ravenous all the time; her energy disappears. Eventually she gives in to her hunger and quickly regains.
After one of these discouraging cycles, a woman might console herself with the thought that she’s no worse off than when she started her diet. Unfortunately, that’s not true. The weight she lost was partly lean tissue, but nearly everything she regained is fat. Because she has less muscle now, it’s going to be harder than ever to lose. What’s more, repeated bouts of yo-yo dieting increase her risk for heart disease and stroke.
Once scientists and doctors understood the key role of muscle in metabolism, they began looking for ways to conserve lean tissue while shedding pounds. The answer turned out to be very simple: strengthening exercise.