Americans are known for having big appetites and serving oversized meals, but doctors worry about how those habits affect the population's health. The Centers for Disease control estimates nearly two-thirds of adults in the United States are classified as overweight, and doctors say the problem is also increasing abroad.
Many blame the fast food industry. Each day millions of Americans flock to fast food restaurants for burgers, hot dogs, chicken sandwiches, and of course french fries.
Physicians such as Dr. Joseph Afram, the head of George Washington University Hospital's Bariatric Surgery Center, say this high-calorie diet causes many Americans to gain weight. "Food is everywhere, and food is encouraged everywhere and high caloric food is encouraged everywhere, starting in childhood," said Dr. Afram.
The CDC estimates nearly one out of every five American children is overweight. Researchers blame sugary snacks like sodas and high-fat, high-protein diets. They also say kids spend long hours in front of the television and computer, so they're not burning all those extra calories.
During the last 15 years, the CDC says the percentage of obese American children and adults has grown. Many experts worry that as overweight kids become overweight adults, they will never learn how to maintain a healthy weight.
Kari Tervo is a 30-year-old member of the popular weight loss club called Weight Watchers. She said, "we all know that to lose weight you have to eat less and move more, but it's kind of nebulous. People don't have a structure. It's kind of like, 'what is eating less?'"
Kari Tervo joined Weight Watchers a few years ago, after she gained nearly 14 kilos while she was in graduate school. She says she was in denial about being overweight for some time. "You know, I'd be pulling on my pants, laying on the floor trying to struggle and I was like, 'oh, those just shrunk in the dryer,'" she said.
Kari said Weight Watchers taught her about monitoring her eating and getting regular exercise. She wears a pedometer to make sure she walks at least 10,000 steps each day. She has learned to cook at home instead of buying fast food. She said she keeps a close watch on what she's eating and how many calories it contains. "Weight Watchers taught me that I can eat whatever I want," she said. "I just have to watch how much of it I eat, and that I have to pay attention to nutrition."
Kari goes to her local Weight Watchers center each week to check on her weight-loss progress. She weighs herself, meets with a Weight Watchers staff member and celebrates when the news is good.
Weight Watchers members say the organization teaches people how to eat healthy for the rest of their lives, and not merely to diet when they are overweight.
But not everyone is able to maintain his or her proper weight through diet and exercise. The CDC says about five percent of Americans are what's called morbidly obese - that's 45 kilograms above their ideal weight. Many go to physicians like Dr. Afram in Washington, DC, for a surgical procedure on their digestive system called gastric bypass.
Dr. Afram said the procedure is major surgery and carries risks because of many patients' health problems. "Patients have high blood pressure, diabetes, heart disease, lung disease, kidney disease, so they are already sick," he said.
Surgeons remove part of the patient's stomach and small intestine. They reattach the shortened intestine to the stomach. This makes the stomach smaller, reducing the amount of food people can eat at one time.
Dr. Afram calls the surgery a "lifestyle operation" because it helps people to change the way they eat.
Jason Jones is one of Dr. Afram's patients. He is a 22-year-old volunteer fireman in Bel Alton, Maryland, who had the surgery two years ago when he weighed nearly 300 kilograms.
"Right before I had the surgery, it had gotten to the point where - well, my life is for the fire department, and it had gotten to the point where I was scared to go into a house fire, because I didn't know what would happen," he said.
Jason's surgery was successful, but his recovery took longer than he thought it would. "It was rough," he said. "I went in on a Monday morning and thought I'd be out by Wednesday. Deer [hunting] season came in on Saturday, and I was thinking I'd be able to go out -- but that didn't happen."
Jason spent months recuperating. But two years later, he says, he has lost almost 140 kilograms and now spends nearly all his time at the firehouse, where he goes out on more emergency calls than any other firefighter.
"Once I was healed, I was good to go - I was out," he said. "Back on the fire trucks, doing my thing."
While American doctors spend long hours trying to understand and counter the nation's obesity epidemic, the growing global weight problem is less understood. Researchers estimate there are about one billion overweight adults worldwide, and the problem is even found in developing countries suffering from undernutrition.
Doctors worry that as changing diets and lifestyles expand waistlines around the world, America's current struggle with obesity could be the world's future.