The end of December always is a great time to recap the year's most important stories. Here's one that deserves more attention than it got at the time, because it may point the way at last to understanding a punishing phenomenon:
Why is it so blasted hard to lose weight and keep it off?
As everyone knows, America is up to its neck in an obesity epidemic, and a big reason why is that slimming down can seem to border on impossible. Some numbers suggest that only about 5 percent of people trying to lose significant amounts of weight succeed at both losing the weight and keeping it off.
Why? What explains this yo-yo phenomenon, especially since it seems to afflict disciplined and less-disciplined people alike?
November brought an intriguing answer. The basic answer is that "the person who's lost weight can't consume as much food as the person who hasn't lost weight," as National Public Radio reported.
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"For example, if you weigh 230 pounds and lose 30 pounds, you cannot eat as much as an individual who has always weighed 200 pounds. You basically have a 'caloric handicap' ...
"And depending on how much weight people lose, they may face a 300-, 400- or even 500-calorie a day handicap, meaning you have to consume that many fewer calories a day in order to maintain your weight loss."
If you're a person who has lost or tried to lose weight, then you probably can recognize both the unfairness and the truth in the above. Few things are more frustrating than watching your friend wolf down ice cream sundaes and stay lean, while you restrict portions and limit desserts but still gain weight.
That's not your imagination, says the latest research. That's a reflection of the way obesity inflicts this caloric handicap, so that the only way to slim down to a "normal" weight and stay there is to eat significantly less than people who've always been at that weight.
Maybe that's why for many people with serious obesity, gastric surgery succeeds where diets had failed. The surgery dramatically restricts the volume of food that can be eaten, helping some number of patients achieve sustained weight loss.
Here's The New York Times on the obesity research:
Scientists "recruited healthy people who were either overweight or obese and put them on a highly restricted diet that led them to lose at least 10 percent of their body weight. They then kept them on a diet to maintain that weight loss."
But a year after the subjects had lost the weight, "the subjects were gaining the weight back despite the maintenance diet -- on average, gaining back half of what they had lost."
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The culprit seems to be hormones, which both slow metabolism and increase hunger in response to weight loss.
The combination of lowered metabolism and stimulated appetite amounts to a "double whammy," as NPR put it.
And the news is that the impact lasts. It's no surprise that hormone levels changed while the participants lost weight, one scientist said. "What is impressive is that these changes don't go away."
Exercise helps. It speeds up metabolism and counters some of the hormonal effects. And in the future, hormone treatments are sure to be studied, too.
But for now, just the findings themselves may be a comfort. To repeat, it's not your imagination. It's biology, and it helps to know where to put the blame.
