"The obesity epidemic has absolutely been exaggerated," said Dr. Vincent Marks, emeritus professor of clinical biochemistry at the University of Surrey.
Marks is among a minority of skeptics who doubt the severity of the obesity problem. They claim that the data about the dangers of obesity are mixed and there is little proof that being fat causes problems including high blood pressure, heart disease and cancer.
Such views contradict nearly everything doctors have been saying for years.
Being fat has long been blamed for conditions like diabetes, which can lead to heart, kidney and nerve diseases. There is also increasing evidence that certain cancers may be linked to weight gain.
"The evidence linking obesity to diabetes and cardiovascular disease is very strong," said Dr. James Hill, director of the Center for Human Nutrition at the University of Colorado. "Type two diabetes rarely happens in people who aren't obese."
But obesity contrarians say that there's no data proving why being fat - in itself - would be dangerous. "There's no good causal connection," said Eric Oliver, author of Fat Politics and a political science professor at the University of Chicago.
Blaming obesity for diabetes and heart attacks, Oliver says, is like blaming lung cancer on bad breath rather than on smoking. Excess weight may actually be a red herring, Oliver says, since other factors like exercise, diet or genetic predispositions towards diseases are harder to measure than weight.
In addition to questioning the dangers of being fat, researchers like Marks also criticize oft-repeated alarmist projections about the rise in obesity -like the British government's warning that nearly half of Britain will be obese by 2050.
Those simply aren't based on good evidence, they say.
According to national health statistics released last month, from 1993 to 2006, "relatively little change" was noted in weight gain, with men and women gaining an average of about 9 pounds. In children, no significant gains were recorded.
The main problem, obesity skeptics say, is that too many people are considered fat, with the obese and overweight often lumped together.
"Being moderately plump is not a health disadvantage," Marks said. "Some overweight people may not look svelte, but they may be perfectly healthy."
As defined by the World Health Organization, anyone with a body mass index above 25 is overweight, and anyone above 30 is obese. Most experts agree the distinctions are imperfect and somewhat arbitrary.
Moreover, Marks and others point to research showing the benefits of a few extra pounds.
In 2005, Katherine Flegal of the United States' Centers for Disease Control and Prevention published a study in the Journal of the American Medical Association, finding that overweight people typically live longer than normal-weight people. More than a dozen other studies have come to the same conclusion.
Outrage ensued. Prominent health experts called the research flawed and worried that people would gleefully supersize their meals.
"I think some experts found it disturbing that we actually said that overweight people have a lower death risk," Flegal said. In other research, Flegal and colleagues found there to be almost no link between death rates and weight.
"The relationship between weight and disease and survival is very complex and we don't have a good handle on why some of these things are related and others are not," Flegal said. She suggested that being fat may help you survive some conditions, but not others.
Doctors have long struggled to explain the obesity paradox - the mystery that in certain conditions like heart attacks, fat patients often have better odds of surviving than thin people. Some experts hypothesize that fat peoples' hearts already work harder than those of thin people, thus giving them a natural edge when their bodies are stressed.
"We don't want people to think it's ok to be heavier," said Hill. "But not everybody who gains weight is going to get heart disease or diabetes," he said.
Some obesity skeptics question the motives of experts who make dire predictions about obesity.
With millions of dollars for obesity researchers, an industry of anti-fat drugs, and a boom in the number of doctors offering surgeries like stomach-stapling, the more fat people there are, the more profits there will be in selling them solutions.
Experts on both sides of the obesity debate have often criticized WHO's overweight and obesity measures, saying they are too low.
When WHO defined the body mass index scores constituting normal, overweight and obese, they appeared to be the result of an independent expert committee convened by WHO.
Yet the 1997 Geneva consultation was held jointly with the International Obesity Task Force, an advocacy group whose self-described mission is "to inform the world about the urgency of the (obesity) problem."
According to the task force's most recent available annual report, more than 70 percent of their funding came from Abbott Laboratories and F. Hoffman La-Roche, companies which make top-selling anti-fat pills.
The task force remains one of Europe's most influential obesity advocacy groups and continues to work closely with WHO.
The blurred lines between pharmaceutical money and obesity groups have also caused concern in Britain. In 2006, one of the country's top obesity doctors quit the organization he founded to combat obesity, the National Obesity Forum, complaining that its goals had been skewed by drug money.
"There's not a lot of money in trying to debunk obesity, but a huge amount in making sure it stays a big problem," said Patrick Basham, a professor of health care policy at Johns Hopkins University.
Still, while skeptics insist that obesity warnings must be taken with a grain of salt, nearly all agree that while a little bit of extra padding may not be too deadly, too much almost certainly is.
"The vast majority of people who get labeled under the obesity epidemic are well under 300 pounds and probably are not facing big health consequences," Oliver said. "It's the morbidly obese people who should be worried."