Summer 2015

All-Fronts Assault on Obesity

Tufts researchers are taking on an epidemic from every angle

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Photo: ingimage.com

The obesity epidemic is not an American phenomenon. About 37 percent of the world’s adults are overweight or obese, and no nation has been able to claim even a tiny reversal in the trend in the last 33 years.

Making a dent in obesity rates is going to take a “global, multidisciplinary, multipronged approach,” said Friedman School Professor Simin Meydani, D.V.M., Ph.D., director of the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA). She spoke at the Tufts Talks Obesity symposium on April 28, a forum that highlighted some of the dozens of researchers at the Friedman School and the HNRCA who are tackling the epidemic from all angles, from cellular discovery to societal change.

Gershoff Professor Alice H. Lichtenstein, D.Sc., who recently finished work as vice chair of the 2015 Dietary Guidelines Advisory Committee, said a lot will depend on how well we educate the next generation about how to hunt and gather in the 21st century, she said. “We really need to empower children to go into the supermarket and make the best choices.”

That’s one aim of ChildObesity180, a partnership of public health, higher education and business leaders directed by Christina Economos, Ph.D., N96, the New Balance Chair in Childhood Nutrition at the Friedman School. Her work on the Shape Up Somerville project was nationally recognized—by Michelle Obama’s “Let’s Move” campaign, among others—for showing that community-based efforts could reduce weight gain in children.

“Our goal is to bring the same obesity prevention solutions that grew right out of Somerville to children across the country to create impact on a massive scale,” she said.

ChildObesity180’s programs have helped communities put physical activity back into the school day, replace sugar-sweetened beverages with water on the sports field and boost kids’ intake of fruits and vegetables. So far, the programs have reached 1.2 million children in all 50 states.

While ChildObesity180 is focusing on the young, Professor Susan Roberts, Ph.D., director of the Energy Metabolism Laboratory at the HNRCA, is working to help adults sort out the barrage of conflicting advice on the best way to lose weight. Dropping pounds is not the same as preventing weight gain, she said, because losing weight puts people up against hunger, a basic human survival mechanism that resides in the unconscious brain.

“We can’t just tell people to have calorie-controlled portions of healthy food and expect that to be easy,” she said, pointing out that hunger originates in the same region of the brain that controls breathing. “Willpower is not going to be very good in addressing those things. We have to work with our neurobiology.”

Her lab has developed a diet plan that controls hunger and reduces cravings and, as brain scans have shown, actually gets people more excited by, say, a grilled chicken breast than a fried drumstick.

“Willpower is not going to be very good in addressing [hunger]. We have to work with our neurobiology.” —Susan Roberts

Other researchers are looking to mitigate the devastating health effects of obesity, which include an increased risk of diabetes and several common cancers. “The effect is a very potent one,” said Professor Joel Mason, M.D., director of the Vitamins and Carcinogenesis Laboratory at the HNRCA, pointing out that merely being overweight sizably increases cancer risk.

“Unfortunately, we’re not going to be able to tackle this problem of obesity in the next five or perhaps even 10 years,” he said. “A lot of us are trying to tease out the biochemical and molecular mechanisms by which obesity promotes cancer, thereby providing us certain targets that we can block.”

Andrew Greenberg, M.D., the Atkins Professor at the School of Medicine and an associate professor at the Friedman School, has conducted groundbreaking research on fat cells and their relationship to high blood sugar and diabetes. Among other things, his lab, the HNRCA’s Obesity and Metabolism Laboratory, is looking at how some bacteria in the intestine can be protective against diabetes.

In addition to discovery in the lab, we might be well served by questioning what we think we already know about obesity. Dariush Mozaffarian, M.D., Dr.P.H., dean of the Friedman School, said that the root cause of obesity is not to be found in the old saw of “calories in versus calories out.”

“It’s not about diet quantity; it’s about diet quality.” —Dariush Mozaffarian

“Saying that obesity is a problem of energy balance is like saying fever is caused by temperature imbalance,” he said.

Any diet can make you lose pounds by cutting calories in the short term, he said, but in the long term—up to 20 years—his research has shown that certain foods are linked to weight gain or loss.

The weight gain associated with sweets and desserts was identical to that from refined grains, making white bread as big a culprit as sugar. Fruits, vegetables, nuts and yogurt were associated with weight loss, while eating more cheese or milk (low-fat or whole) made little difference.

“This is really where the modern science is taking us,” he said. “It’s not about diet quantity; it’s about diet quality.”

He added that the school is now evaluating, with funding from the National Institutes of Health, how different policies, from media and education to locations of supermarkets to taxes and subsidies, can improve nutrition and reduce obesity in the United States.

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