Rethinking Weight-Loss Strategies

A study suggests that we need to watch those sources of carbs and protein

When it comes to losing weight, food combination might matter as much as individual food choices, according to new research.

The study, published in The American Journal of Clinical Nutrition, followed the dietary habits of 120,000 U.S. health professionals over 16 years. Unsurprisingly, processed and red meat protein sources and refined carbohydrates, such as hamburger meat and French fries, were associated with weight gain, while such foods as fish, nuts and whole grains were associated with moderate weight loss over time.

Interestingly, full-fat dairy products, including milk, cheese and butter, were not associated with weight gain, and yogurt was associated with weight loss. “When people consumed more low-fat dairy products, they actually increased their consumption of carbs, which may promote weight gain,” says Jessica Smith, a visiting scholar at the Friedman School and first author on the study. “This suggests that people compensate over years for the lower calories in low-fat dairy by increasing their carb intake.”

And increasing carbohydrates is not always good, especially if they have a high glycemic load, a measure of how a food affects blood sugar. Researchers found that when people simultaneously increased foods high in glycemic load and protein sources like red meat, there was a stronger association with weight gain. Similarly, while eating fish was linked to weight loss, that association decreased when the diet overall was high in glycemic load.

This is one of many studies leading nutrition experts to advise consumers to pay more attention to overall diet pattern and less to individual “good” or “bad” foods. “Focus on quality, not quantity of your diet,” says Dariush Mozaffarian, dean of the Friedman School and senior author on the study. “Foods are diverse, and interact with our bodies and each other in complex ways. Increase fish, yogurt, nuts, fruits and whole grains in your diet, and reduce potatoes, white bread and rice and sugars.”

A version of this article first appeared in the Summer 2015 issue of Tufts Nutrition magazine.

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