Scientists at the Obesity Research Center, St. Luke's-Roosevelt Hospital in New York City, assigned 14 overweight but otherwise healthy people to a diet group; 9 other overweight people served as controls. The diet group was given a very-low-calorie diet for four weeks, while the control group didn't alter any of their eating habits at all.

Before starting anyone on the low-cal diets, the researchers used a special balloon device to measure stomach capacity, or the volume each of the subjects' stomachs could hold. Not surprisingly, there was no difference between the two groups--both could hold about 4 cups.

After a month of dieting, the groups were tested again. The result: The dieters' stomach capacities had shrunk by 27%. Now their stomachs could only hold about three cups volume, the same capacity of normal-weight people, says Allan Geliebter, PhD, lead researcher and associate research scientist. Along with smaller stomachs, the dieters ended up 20 pounds lighter on average (American Journal of Clinical Nutrition, February 1996).

Back in the '80s, Dr. Geliebter began exploring the link between large stomachs, large appetites and large amounts of body fat. These studies found that animals who were offered food infrequently--skipping a day or more--packed away huge meals when they were fed. Their stomachs grew much larger than the stomachs of animals fed small, frequent meals--and so did the rest of their bodies.

Next, Dr. Geliebter's team discovered that the stomachs of overweight people held more volume than the stomachs of normal-weight people. And they found that normal-weight bulimics--people who binge on huge meals and then force themselves to vomit--had even larger stomach capacities than overweight people. So he suspected it's not just being physically larger in size that makes the stomach big but a specific pattern of eating large amounts of food at one sitting.

Stretching: The Truth

What exactly does the stretching? Not eating a bowl of cereal at 6 a.m. and a piece of fruit at 8, says Dr. Geliebter. It appears that meals the size of 2 to 2 1/2 cups may be best for shrinking your stomach down to size. That may not sound like much, but you get six mini-meals a day. With less time between feedings, you're less likely to feel hungry as your stomach recedes. Keep in mind, though, to fill the meals with low-calorie, low-fat choices. A cup of M&Ms won't stretch your stomach, but the 840 calories won' t do much for your waistline either. 

Stomach stuffing--packing in huge amounts of food at one sitting--seems to be the culprit. And that eating pattern is particularly common among overweight people. Many overweight people skip breakfast and have a very small lunch. That's probably not enough time to shrink stomach capacity. And, by the time their dinnertime rolls around, they're ravenously hungry and devour huge volumes of food. Night after night following this eating routine might eventually increase stomach capacity.

The now-larger stomach requires more food to feel full, Dr. Geliebter adds. Just as your car's gas tank signals the gas pump to shut off when it's full, stretch receptors in the stomach send signals to the brain when you've eaten your fill. Dr. Geliebter speculates that the stomach must be filled to about 70% before the stretch receptors are activated. So a person with a normal stomach capacity (about 3 cups) feels full and stops eating after about 2 to 2 1/2 cups of food. Whereas a person who's stretched their stomach may need to eat 3 or more cups of food to feel equally satisfied. And that, usually means more calories and fat.

Shrink Wrap

Put on the pressure. While you're waiting for your stomach to grow smaller on the inside, you can make it feel smaller from the outside. Research by Dr. Geliebter shows that applying pressure across the abdomen causes people to eat less. Formfitting clothes or a snug belt that exerts a little extra pressure on your belly might discourage you from overeating, he says.

Mini-Meals

Fortunately, reversing this process is easier than you think. "In our research, we reevaluated the dieters after a month, so we don' t know exactly when their stomach capacities began to shrink," says Dr. Geliebter. "But if I had to guess, I'd day the process of altering stomach capacity begins in a matter of days."

That sounds reasonable. Remember your last bout of the flu. You lived on chicken soup for two days. And when you went back to normal foods, you were full after two bites. But rest assured you don't have to suffer through the flu or go hungry to whittle your stomach down to size. Here are some healthy, satisfying ways to start the shrinking process:

Eat minimeals. "The notion that we should eat small, frequent meals to lose weight isn't new, but this research does support it," says Dr. Geliebter. "Distribute food over many small meals during the day, " he suggests. "Don't skip breakfast or lunch, because that may cause you to feel deprived later in the day." And if you feel deprived, then you may be more likely to eat huge, stomach-stretching meals in the evening. 

Exercise fat-and-calorie control. A small volume of food doesn't always equate to a small amount of calories and fat. Focus on low-calorie, low-fat foods, even while controlling the volume of the food you eat. No matter how you slice it, a total of 2 1/2 cups of roast beef at 518 calories and 23 grams of fat is a worse choice than 2 1/2 cups of steamed vegetables with just 168 calories and 0.6 g. of fat.

Here's a one-day, mini-meal sampler that keeps volume, calories and fat all in line.

Breakfast

Oatmeal and raisins

A.M.

Yogurt and apple

Lunch

Pasta, roll and a salad,

Mid-afternoon

Orange and a bagel

Dinner

Baked tofu and broccoli

P.M.

Pretzels