This week marks the beginning of the gluttony season, the time when even the most health-conscious diner succumbs to the temptations of the holiday buffet.
But is pigging out during the holidays a harmless indulgence or a real health worry? Indigestion, flatulence and the need to unbutton tight pants are the most common symptoms triggered by the Thanksgiving Day binge. But vast helpings of turkey, stuffing and candied sweet potatoes can take a more serious toll. Big meals can raise the risk for heart attack, gallbladder pain and dangerous drowsiness on the drive home.
Every bite of food, whether it's part of a huge Thanksgiving meal or a weekday lunch, travels on its own fantastic journey through the body, touching off a simultaneous release of hormones, chemicals and digestive fluids. The average meal takes 1 to 3 hours to leave the stomach. But a large meal can take 8 to 12 hours, depending on the quantity and fat content.
The average American consumes about 4,500 calories and 229 grams of fat throughout Thanksgiving Day, according to the Calorie Control Council, which represents makers of low-calorie foods. "It's like a tsunami of fat coming into the body," said Dr. Pamela Peeke, assistant clinical professor at the University of Maryland School of Medicine.
Average stomach capacity is about 8 cups, although it can range from 4 to 12, said Dr. Edward Saltzman, an assistant professor of medicine at Tufts University. A stretched stomach prompts the release of chemicals that tell the brain it's full. But some holiday diners, faced with a sumptuous buffet of mashed potatoes and gravy, green bean casserole and pumpkin pie, keep eating.
Experts say the ability to ignore satiety signals is an evolutionary adaptation that helped build fat stores during times of plenty. Even so, the body eventually puts a stop to the binge. After about 1,500 calories in one sitting, the gut releases a hormone that causes nausea, says Susan B. Roberts, director of the energy metabolism laboratory at Tufts.
Although your stomach may feel as if it will burst, gastric rupture is extremely rare, notes Dr. William Goldberg, a New York emergency room physician whose book "Why Do Men Have Nipples?" explores the issue. The problem is usually limited to people with major eating disorders; in a study of people who had died with Prader-Willi syndrome, which causes excessive overeating, about 3 percent of the deaths were due to stomach rupture, said Dr. David Stevenson, an assistant professor at the University of Utah.
But while your stomach won't burst after a big Thanksgiving meal, overeating will make your body work harder. The extra digestive workload demanded by a food binge requires the heart to pump more blood to the stomach and intestines. Heavy consumption of fatty foods can also lead to changes that cause blood to clot more easily, said Dr. Francisco Lopez-Jimenez, a researcher at the Mayo Clinic College of Medicine.
As a result, heart attack risk appears to surge. Dr. Lopez-Jimenez led one study of 2,000 people that showed a fourfold increase in heart attack risk in the two hours after eating a big meal. Israeli researchers reported a sevenfold risk. "Someone who eats three times the normal calories of a regular meal will have an extra workload for the stomach and intestines and therefore the heart," Dr. Lopez-Jimenez said.
Dr. Goldberg says the digestive workout may also explain the "food coma" many people experience after a big meal. Although popular wisdom holds that Thanksgiving drowsiness is caused by tryptophan, an amino acid found in turkey, Dr. Goldberg notes that the amount isn't significant enough to affect most people.
For most people, food fatigue just brings on the need for a nap, but for travelers it is also a safety risk. "A lot of families as soon as they are done eating say, 'Let's get back on the road,'" said Dr. Carol Ash, the medical director of Sleep for Life, a sleep disorders program in Hillsborough, N.J. Dr. Ash notes that food fatigue, along with holiday alcohol consumption, the monotony of driving and a natural circadian dip late in the day all make for a lethal combination behind the wheel.
As the stomach releases food into the intestines, the gallbladder begins to squeeze out bile to help with fat digestion. Like the rest of the body, it has to work harder after a big meal — a frequent cause of gallstone attacks, which occur when clusters of solid material get stuck in the narrow duct that connects the organ to the intestine. These attacks are seldom fatal, but the pain mimics a heart attack and can be excruciating. Many people don't know they have gallstones until an attack occurs.
Large meals increase the risk for flatulence, because bits of undigested food slip into the colon and begin to ferment. And people with existing health problems that require special diets have to be careful about their intake of salt, fat and calories at Thanksgiving.
Simple strategies can help minimize the gluttony. Keep the serving dishes in the kitchen, so you won't take extra helpings mindlessly. Use smaller serving spoons and plates. In one study, Brian Wansink, a researcher at Cornell University, found that the bigger the bowl and serving spoon, the more ice cream people tended to eat.
Stick to foods that require utensils — we eat finger foods faster than those that require a fork.
Finally, contribute to the dinnertime conversation. The more you talk, the less you'll eat.
Copyright 2007 The New York Times Company