It’s not only the food industry that is producing more low-cost food than we can eat. It’s not only our restaurants, which are serving bigger portions than ever. It’s not only a wealth of labor-saving devices, ranging from our cars to our electric can openers. And it’s more than the news and entertainment that we effortlessly get sitting in front of a TV screen or computer monitor.
It’s our own bodies too.
More than 85 percent of those of us with diabetes are overweight. Few of the other 15 percent who are at normal or below normal weight got there by dieting. Many of them have type 1 diabetes and were never overweight.
It’s so hard to change our weight because our bodies like the status quo. When we take off a lot of weight our body compensates for what is sees as the threat of starvation. Our metabolism slows down. Our body uses the calories we give it more slowly.
Our body tends to reach its set point between weight and energy expenditure. Scientists call this homeostasis.
Three Rockefeller University M.D.’s, Rudolph L. Leibel, Michael Rosenbaum, and Jules Hirsch provided the most famous demonstration of the set-point theory. Strangely, however, they didn’t called it our set point. Instead, to them it is compensatory metabolic processes that resist the maintenance of our new, lower, weight.
They monitored the metabolic rates of research subjects whom they put on tight diets and exercise programs. When the volunteers got more food, their metabolic rates went way up. But when they got much less food, their metabolic rates fell, preserving the status quo.
The set point of our weight is why few of us keep off the weight that we go to so much trouble to lose. When we try to reduce our weight below the point that our body is naturally set to have, our bodies begin to slow down.
I know. I lost a lot of weight last year when I added Byetta to a diet and exercise program. The trouble is that the more weight I loose the less I can eat without gaining it back.
As we lose weight, not only is our resting metabolic rate decreased, but our nonresting energy expenditure is also less, because we are moving less mass around, which takes less effort.
To keep our weight below our natural set point means that we have to do at least two things:
1. We have to keep watching what we eat and continually eat less as our weight and metabolism goes down.
2. We have to exercise regularly to keep our metabolism up to speed. Because physical activity increases our energy expenditure and counteracts the reduction in our total energy expenditure, it is a key component of any weight loss program.
Studies of people who are successful at keeping weight off show that they need to devote at least an hour a day to increasing their physical activity. But they activity doesn’t have to be high intensity. Walking and taking the stairs rather than the elevator can make the difference.