10 Foods That Drive Weight Gain and Loss Identified by Harvard

A journal article published today examines the long-term impacts of small but significant lifestyle changes—especially to diet

In a new report published today in The New England Journal of Medicine, a team of Harvard researchers has revealed the results of a study of 120,877 people showing that small changes in lifestyle behaviors such as physical activity, sleep duration, and TV-watching are strongly correlated with long-term weight gain. But the most important factor was diet—and among the report's most intriguing findings is precisely how much weight gain (or loss) can be attributed to consuming an additional daily serving of a variety of specific foods over a four-year period.

The following 10 foods were found to be especially correlated with long-term changes in weight (the first five foods promoting weight gain, the second five promoting weight loss):

How much did each food affect weight over a four-year period? Here's a chart that sums up the findings (with each bar indicating the total pounds gained or lost over four years, on average, as a result of consuming an additional daily serving of that particular food):

To conduct their study, the researchers evaluated three large cohorts—from the Nurses' Health Study (NHS), the Nurses' Health Study II (NHS II), and the Health Professionals Follow-up Study (HPFS)—of people who were free of chronic diseases and not obese at the start of the evaluation process. They measured specific lifestyle factors and weight gain every four years, with follow-up times ranging from 12 to 20 years.

One striking if somewhat predictable takeaway from the study is that focusing on overall dietary quality—such as eating less refined sugars and refined grains and more minimally processed foods—is probably more important to long-term health than monitoring total calorie or fat intake or other nutritional markers. As co-author Frank Hu, professor of nutrition and epidemiology at the Harvard School of Public Health, stated in a press release accompanying the announcement of the report, "The idea that there are no 'good' or 'bad' foods is a myth that needs to be debunked."

For more information on the report, you can watch the following video of the lead author, Dariush Mozaffarian, discussing the findings, or visit the Harvard School of Public Health's website.

Diet, Lifestyle, and Long-Term Weight Gain from Harvard School of Public Health on Vimeo.

Main image: Tavallai/flickr