David Allison is a renowned scientist who runs an obesity research center at the University of Alabama in Birmingham. He has a 108-page resume and was honored at the White House.
But even though study after study have shown soda to be a significant contributor to America's staggering obesity crisis, he says there is too little "solid evidence."
Meanwhile, the Centers for Disease Control last week warned teenagers to cut down on their soda consumption, citing studies that show soda contributes to obesity and other health problems such as diabetes.
Allison has said such studies haven't been rigorous enough to prove soda contributes to obesity, but critics say his skepticism stems from his financial ties to entities such as Coca-Cola, Pepsi and the American Beverage Association, who, critics say, have paid Allison to poke holes in the scientific consensus.
"And then his articles can be cited by the companies, can be used to say, 'Look at this article in a major journal concludes we don't know yet if sugar sweetened beverages are bad for children and adult health,'" said Barry Popkin, a food researcher at the University of North Carolina.
It's not just soda companies. Allison has also taken money from Kraft, McDonald's, General Mills, Kellogg's, Mars and Nabisco, according to his financial disclosures.
Allison, who studied at Hofstra, Johns Hopkins and Columbia universities, was paid by the New York Restaurant Association to file an affidavit in its case against New York City and its law requiring restaurants to post calorie information on menus, saying the law might actually make people eat more.
His actions outraged many of his colleagues and Allison eventually submitted his resignation as the incoming president of the Obesity Society over the controversy that followed the filing of his affidavit, which he signed as president-elect of the Obesity Society.
Allison has also taken an industry-friendly stance when it comes to breast feeding.
The International Formula Council funded Allison's research questioning the World Health Organization's assertion that breast-feeding cuts a child's risk of obesity. The paper was published in the November 2008 issue of Obesity Reviews.
Critics say Allison is part of a concerted effort by big food to co-opt scientists not only by funding their research but by offering them lucrative speaking and consulting deals, in an effort to confuse U.S. families about the health effects of popular food products.
Such tactics, critics say, are similar to those once used by Big Tobacco.
In a recent commentary in the Journal of the American Medical Association, respected food researchers asserted that the industry has participated in "deceptive science and advocacy." They say "the food and beverage industry has created or funded front groups reminiscent of the tobacco institute that give the appearance of grassroots support."
The groups, they say, include Americans Against Food Taxes and the Center for Consumer Freedom, organizations that are largely funded by the food and beverage industries.
"Big tobacco, big sugar," food researcher Popkin said, "identical in the way they treat scientists."
Popkin admits he has taken some industry money for research but, he says, turned down many of big food's most tantalizing offers.
"I've been offered $5,000 to go speak to this meeting or that meeting," he said. "You get $2,000 to $5,000 a day. They'll fly you on business class tickets to exotic places. They'll take you to Paris or Rio. They'll take you to places in Brazil."
The food companies don't just fund individual scientists; they also give money to entire groups.
The Children's Hospital of Philadelphia was criticized for taking $10 million for obesity research from the soda industry, and after the American Association of Family Physicians took money from Coca-Cola, some members ripped up their membership cards.
Both groups say their scientific conclusions are not affected by industry funding.
American Beverage Association Calls Allegations Baseless
The American Dietetic Association took money from Hershey to collaborate on a "Moderation Nation" website, to reach millions with a healthy-eating message, they said. Some obesity experts were appalled that it included recipes such as "Fudgey Fruit Pizza" and "Crispy Chocolate Ice Cream Mud Pie," which has 14 teaspoons of sugar in each slice.
In a statement, the ADA defended the program, saying that website helped deliver healthy eating messages to a wider consumer audience than it otherwise could.
"Our 'total diet' approach follows the new USA MyPlate, with a focus on the role of fruits, vegetables, low-fat dairy, lean protein choices and whole grains," the statement said. "When individual consumers choose wisely 80 to 90 percent of the time, they can also include an occasional treat."
Representatives from the food industry, including the American Beverage Association, said the notion that industry money taints the scientific research is "baseless."
As for Allison, although he has received tens of millions of dollars in research grants from the government, he has also received at least $2.5 million in research grants from private industry, ABC News has learned.
The $2.5 million doesn't include any consulting or speaking fees he has received from industry or any money he has received from Coke, Pepsi, or the American Beverage Association.
His employer, the University of Alabama, said some of his research contradicts the interests of his corporate sponsors.
Allison turned down ABC News' repeated requests for an interview. When ABC News confronted him early one morning at a convention in Washington D.C., he had no comment when asked if he was a "hired gun" for the food industry.
He has said that he is happy to be involved in the pursuit of truth and, sometimes, amid that pursuit, he might help the government or groups such as the restaurant industry.