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Unfortunately, existing research cannot provide a definitive test of our hypothesis. Several prominent clinical trials reported no difference in weight loss when comparing diets purportedly differing in protein, carbohydrate and fat. However, these trials had major limitations; at the end, subjects reported that they had not met the targets for complying with the prescribed diets. We wouldn’t discard a potentially lifesaving cancer treatment based on negative findings, if the research subjects didn’t take the drug as intended.
There are better ways to do this research. Studies should provide participants with at least some of their food, to make it easier for them to stick to the diets. Two studies that did this — one by the Direct Group in 2008 and the other by the Diogenes Project in 2010 — reported substantial benefits associated with the reduction of rapidly digestible carbohydrate compared with conventional diets. We need to invest much more in this research. With the annual economic burden of diabetes — just one obesity-related complication — predicted to approach half a trillion dollars by 2020, a few billion dollars for state-of-the-art nutrition research would make a good investment.
If this hypothesis turns out to be correct, it will have immediate implications for public health. It would mean that the decades-long focus on calorie restriction was destined to fail for most people. Information about calorie content would remain relevant, not as a strategy for weight loss, but rather to help people avoid eating too much highly processed food loaded with rapidly digesting carbohydrates. But obesity treatment would more appropriately focus on diet quality rather than calorie quantity.
People in the modern food environment seem to have greater control over what they eat than how much. With reduced consumption of refined grains, concentrated sugar and potato products and a few other sensible lifestyle choices, our internal body weight control system should be able to do the rest. Eventually, we could bring the body weight set point back to pre-epidemic levels. Addressing the underlying biological drive to overeat may make for a far more practical and effective solution to obesity than counting calories.
David S. Ludwig directs the New Balance Foundation Obesity Prevention Center at Boston Children’s Hospital and is a professor of pediatrics at Harvard Medical School. Mark I. Friedman is vice president of research at the Nutrition Science Initiative. They wrote this article for the New York Times.
The Opinion section is produced by the Editorial Department to foster discussion about key issues. The Editorial Board represents the institutional voice of the Star Tribune and operates independently of the newsroom.