THE GIST

- Drinking alcohol with a rich meal slows digestion by as much as 50 percent.

- By slowing digestion, alcohol can also make you feel fuller longer, though it's not clear what that means for nutrient absorption or weight gain.

- If you are prone to stomach distress, it might be best to go with water or tea instead.

For many people, a glass of wine helps make food feel like it's going down more smoothly. But drinking alcohol with a rich and fatty meal causes food to linger in the stomach longer, found a new study -- leading people to feel fuller over a greater period of time.

The findings offer new insight into the complicated and multi-faceted ways that alcohol interacts with digestion and appetite. The study, which analyzed people as they ate cheese fondue, may also help settle a long-standing debate among Europeans about which beverage is best to drink with a popular and festive dish.

"In Switzerland and other parts of Europe, there is a big debate when families get together about what they are going to drink with fondue," said Mark Fox, a gastroenterologist at the Nottingham Digestive Diseases Center in the United Kingdom. He worked on the study while at the University of Zurich.

"Half say you should drink white wine because it dissolves the cheese," he said. "The other half says you should drink warm tea because wine turns the cheese into a solid mass. All are completely old wives' tales."

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Fondue-lovers also argue about whether a shot of spirits after the meal will further reduce the discomforts of eating such a rich and gooey dinner.

Previous studies have shown that drinking an alcoholic beverage before a meal increases appetite and causes people to eat a bit more than they would otherwise.

To find out how drinking during and after a meal might add to the story, Fox and colleagues fed a meal of bread and Swiss cheese fondue to 20 healthy adults who hadn't eaten anything for six hours beforehand.

Half of the diners were assigned to sip about 10 ounces of white wine at regular intervals throughout the meal. The other half drank the same volume of black tea at the same intervals. Both groups ate equal amounts of bread and fondue, which was made with Gruyere and Fribourgeois cheeses. The meal contained about 780 calories, 52 grams of protein, 150 milligrams of sodium and 64 grams of fat.

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An hour and a half later, half of each group was again chosen at random to drink a shot of cherry schnapps. The other half drank a shot of water. Throughout the meal, the scientists gave diners breath tests that measured a type of weighted carbon and revealed how slowly or quickly their stomachs were churning up the food.

One of the most striking findings, Fox said, was how incredibly slowly the stomach empties a cheese fondue meal, no matter what you drink.

Extrapolating from their measurements, he estimated that it would take six hours for the stomach to completely empty itself in the group that drank tea and water. By comparison, the process of gastric emptying would take nine hours in those who drank both wine and Schnapps.

For the wine-drinkers, the researchers report today in the journal BMJ, digestion slowed along with the first sip. After chugging schnapps, the rate also dropped immediately.

"There's something we call 'cheese baby syndrome,'" Fox said. "You just feel like you're pregnant, like these big lumps of cheese are still sitting in your stomach."

Tea drinking might have had the opposite effect: There is some evidence in rats that tea actually speeds up gastric emptying. But the volume of tea used in this study was so small, Fox said, that he imagines that drinking water would produce the same results.

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With their fuller stomachs, the wine-drinkers expressed less interest in eating dessert after the meal than the tea-drinkers did, though there was no difference between groups in how uncomfortable they felt. That suggests, Fox said, that healthy people can probably drink whatever they want with fondue and feel just fine.

For people who are prone to bloating and digestive distress after a rich meal, on the other hand, drinking alcohol with food might help relax the stomach at first, soothing symptoms. As the hours wear on, though, discomfort might be worse than if they had chosen tea or water instead.

It's impossible to say from this study whether drinking alcohol with a meal might affect how much food people eat or how much weight they gain or lose, said Thomas Abell, a gastroenterologist at the University of Mississippi Medical Center in Jackson.

Instead, the findings bring us one small step closer to understanding the complicated interactions between our behaviors and our bodies.

"To think about how little is actually know about something millions and billions of people do every day is pretty amazing," Abell said. "It's an important article in that way. We do these things all time, and we don't know very much about them. The body is so complex."