Not that we needed more evidence, but new research is explaining just why it’s so hard for most people to lose weight and maintain the loss.
I already knew about this from personal experience and observation. And don’t get me wrong—I’ve never been fat, but I’m one of those people who is always trying to lose ten to twenty pounds to look and feel what I’d consider my best. Trouble is, this comes at the price of a sort of mild but steady starvation, an experience I’m not willing to voluntarily endure for more than a few weeks or months at the most. Plus, my weight loss is agonizingly slow (and this despite the fact that my nutrition is good, and I already exercise virtually every day) and my rebound weight gain is astoundingly fast.
In other words, I can diet for months and lose about five pounds total, and I can regain that five in just a couple of days of eating what most people would call normally. Although the tendency has gotten worse as I’ve gotten older, twas ever thus. Even when I was young I had to severely limit my calories in order to maintain my dance weight (very slender), despite the fact that I was highly active on a daily basis.
Your mileage—and poundage, and diet experience—may differ, especially if you happen to be a man. Men are generally bigger, less affected by weight-clingy hormones such as estrogen, and with bodies that have a higher proportion of metabolically active muscle.
In Lancet, Dr. Kevin D. Hall and his colleagues at the the National Institute of Diabetes and Digestive and Kidney Diseases have described “a more realistic model of how the body responds to changes in caloric intake and expenditure, basing their calculations on how people of different weights responded to caloric changes in a controlled setting like a metabolic unit.” So this study is not relying on such inherently suspect measures as people’s reports of what they’re eating and how much they’re exercising; it rests on more exact measurements than that.
The news isn’t pretty, but it reinforces what I’ve long suspected and also observed among my heavier friends, most of whom don’t seem to eat all that much:
According to the researchers, it is easy to gain weight unwittingly from a very small imbalance in the number of calories consumed over calories used. Just 10 extra calories a day is all it takes to raise the body weight of the average person by 20 pounds in 30 years, the authors wrote.
Furthermore, the same increase in calories will result in more pounds gained by a heavier person than by a lean one — and a greater proportion of the weight gained by the heavier person will be body fat. This happens because lean tissue (muscles, bones and organs) uses more calories than the same weight of fat.
In an interview, Dr. Hall said the longstanding assumption that cutting 3,500 calories will produce a one-pound weight loss indefinitely is inaccurate and can produce discouraging results both for dieters and for policy changes like the proposed tax on sugar-sweetened beverages.
If the 3,500-calorie rule applied consistently in real life, it would result in twice the weight loss that the new model predicts, the authors wrote. This helps to explain why even the most diligent dieters often fail to reach weight loss goals that were based on the old rule.
A more realistic result, he said, is that cutting out 250 calories a day — the amount in a small bar or chocolate or half a cup of premium ice cream — would lead to a weight loss of about 25 pounds over three years, with half that loss occurring the first year.
Why is this bad news? Well, for starters, people like me are not eating small chocolate bars or half a cup of premium ice cream on a daily basis. Some of us have already pared our daily calorie consumption done to the bone.
Do the math: if a person is losing 25 pounds over three years, that’s approximately 8 pounds a year or about 2/3 a pound a month. Hardly enough to provide the motivation to keep the struggling dieter going. Plus, how many people have such an exact idea of their daily caloric consumption that they can consistently cut back that much, not to mention doing it for that long? If the weight loss rate is so slow, just a couple of days a month of special treats (on special occasions, for example) can undo all the good of the far more numerous days of deprivation, just as I’ve observed. The requisite consistency of denial is more than most mortals can manage, especially with the constant temptation of wonderful food at the grocery store, in advertisements, and at social events.
It’s not surprising that most people have trouble keeping the weight off. The wonder is that anyone ever succeeds, considering what’s required.