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"Weight reduction brought about by caloric restriction caused ghrelin
levels to increase, suggesting that ghrelin might contribute to the drive to eat
that makes long-term success with dieting so rare."
Editorial, The New England Journal Of Medicine, May 23, 2002
Stomach Hormone Foils Weight Loss Efforts
Itís common knowledge that losing weight is much easier than keeping it off. Complex body mechanisms, which in ancient times helped us survive when food supplies were unreliable, make it hard to lose weight and keeping it off in modern times when high-calorie food is readily available. Weíre learning more all the time about the bodyís exquisite systems for keeping weight on an even keel. "Recent years have witnessed explosive growth in knowledge of the physiological factors regulating appetite and weight control," wrote Drs. Jeffrey S. Flier and Eleftheria Maratos-Flier, in a New England Journal of Medicine editorial, which accompanied a report on the latest discovery.
Leptin, discovered in 1995, is a hormone which suppresses the appetite. Produced primarily in fat tissue, leptin circulates generally in proportion to fat stores. It encourages people to stop eating when their fat cells are full. A newly discovered hormone called ghrelin (pronounced GRELL-in) seems to have the opposite effect.
Experiments on rats and mice found ghrelin to be a powerful appetite stimulant; rodents given the hormone immediately began feeding. And British researchers last year found that human volunteers injected with ghrelin became ravenous and immediately increased their food intake.
When weíve stored enough fat, leptin tells us to stop eating. Ghrelin, on the other hand, tells us to eat and store fat. In ancient times, ghrelin helped us prepare for the next famine. In modern times, however, it acts as the evil twin of leptin. When we go on a diet and lose weight, ghrelin makes us hungry. The body thinks we are starving and encourages us to eat and regain the weight.
In the new study, published May 23, 2002 in The New England Journal of Medicine, a team of Seattle scientists, headed by Dr. David E. Cummings of the University of Washington, measured daily fluctuations of ghrelin in 13 obese subjects before and after a six-month weight-reduction program. The subjects, who weighed an average of 220 pounds before the study began, lost an average of 38 pounds in three months with a combination of diet and exercise, and kept it off for three more months.
The researchers found that ghrelin rose sharply before meals and fell shortly after meals, confirming earlier studies showing that it triggers the desire to eat. After the subjects lost an average of 17 percent of their body weight, ghrelin output rose roughly 25 percent. In fact, their lowest ghrelin levels after the diet-induced weight loss were nearly as high as the pre-meal peaks at the start of the study.
"Itís well known that your body works against you when you try to lose weight," Dr. Cummings told Time magazine. "Whatís new, is the possibility that a rise in ghrelin is the way itís done."
The researchers didnít follow the subjects after the study ended, but they expect that most of them regained the lost weight. One participant told The Wall Street Journal he felt "hungry all the time," during and after the experiment. He regained everything he lost, plus 15 more pounds, The Journal reported.
The Stomach Bypass Connection
The evidence that ghrelin helps to control appetite and body weight "remains largely circumstantial," according to the editorial in The New England Journal of Medicine. Another aspect of the study, however, provides additional support.
The Seattle researchers also measured ghrelin levels in five subjects who had stomach bypass surgery. "Despite a 36 percent weight loss... the ghrelin profile in the gastric-bypass group was 77 percent lower than in normal-weight controls and 72 percent lower than matched obese controls," the researchers reported. In the other words, people who lost weight following stomach bypass surgery had very low ghrelin levels compared to obese subjects who had lost the same amount of weight and compared to people of normal weight. Whatís more, ghrelin levels in people who had the surgery didnít even rise before meals as it does in most people.
This may explain why people who undergo gastric-bypass surgery are remarkably successful in losing weight -- and keeping it off. Some patients have lost as much as 300 pounds and kept the weight off for a decade or more, according to The Washington Post. "Itís nowhere near like dieting and exercise, where almost universal weight regained is seen," Dr. Cummings told The Post. "We propose that the loss of ghrelin... may be the explainer," Cummings added.
In gastric bypass, surgeons sew off all but a tiny pocket at the top of the stomach. This, of course, limits food intake. Apparently, it also shuts down the production of ghrelin to a barely detectable level.
One might expect that those who have had the surgery would make up for the reduced size of their stomach by eating many small meals over the course of the day. But most of them apparently donít. In fact, they seem to lose interest in food. One person who had the surgery told The Wall Street Journal that he often doesnít notice heís hungry until his blood sugar in so low that he feels faint. He actually has to remind himself to eat.
Most of the articles on the Seattle study highlight the prospects for new drugs to suppress the production of ghrelin and help people keep weight off. "Every pharmaceutical company I know" is hunting for drugs that stymie the action of ghrelin, Dr. Cummings told The Wall Street Journal.
Newsweek speculates that future weight-control treatments may include a "leptin-ghrelin drug cocktail."
I see a different take home message. Itís a hopeful message that can be acted on immediately.
We donít need drugs. And except in cases of gross obesity, where rapid weight loss is medically necessary, we certainly donít need gastric bypass surgery.
As my friend Laszlo noted, losing 38 pounds in three months is too fast. That's more than three pounds a week. As mentioned earlier, one of the subjects told the Wall Street Journal he was, "hungry all the time." He obviously felt deprived.
No wonder protective hormone levels skyrocketed.
As I see it, the ghrelin study reinforces my advice in Ripped 2: Reduce calories "slightly" and increase activity "slightly." Lose weight slowly. Donít try to force the process. Ease your weight down. Never allow yourself to be hungry or feel deprived. Donít set off alarm bells designed for times when life was hard and food was scarce. Donít take drastic action which makes the body think survival is at issue.
Avoid actions that might trigger the release of ghrelin and suppress leptin.
Like the man interviewed by The Wall Street Journal who had stomach-bypass surgery, I rarely feel hungry or deprived -- even when I'm trying to lose weight -- but for different reasons.
I always lose slowly. Except on holidays and special occasions, I avoid foods and situations which encourage overeating. I eat regular meals and try to keep my blood sugar on an even keel. I stay ahead of the curve. I try never to be out of control at mealtime.
This formula has kept me lean for almost three decades. It will work for you as well.
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