Examining the “secrets” to staying thin

Keeping the pounds from adding up in the first place might be easier than trying to diet them off later. To investigate this idea, researchers from Brigham and Women’s Hospital, Harvard Medical School, and the Harvard School of Public Health set up a study to shed some light on those factors that help people stay trim or contribute to weight gain over time.

Participants were part of the Nurses’ Health Study I and II and the Health Professionals Follow-up Study. At the beginning of the study, 120,877 healthy, non-obese people provided their height and weight and information about their diet and lifestyle habits. This information was updated every four years for 12 to 20 years.

The participants also reported on their physical activity, television watching, alcohol use, sleep duration, and smoking history.

Eat less of this and more of that

The people gained an average of 3.4 pounds during each four-year interval—an amount that could add up to 17 pounds over 20 years. Almost every dietary and lifestyle factor investigated had some impact on weight gain over the years, the effects of which were similar among men and women.

Eating more of these foods led to the most weight gain:

• Potato chips
• Potatoes
• Sugar-sweetened beverages
• Unprocessed red meats
• Processed red meats

Eating more refined grains, sweets, and desserts also led to weight gain over the years.

Eating more of these foods led to weight loss:

• Vegetables
• Whole grains
• Nuts
• Yogurt

But there is more to the story than just “eating a lot of hot dogs will make you fat,” or “eating a lot of vegetables will make you thin.” People who ate less of the healthier foods were also more likely to gain weight. And simply eating fewer “unhealthy” foods led to less weight gain.

“Our findings suggest that strategies to help people consume fewer calories may be most effective when particular foods or beverages are targeted for decreased (or increased) consumption,” the researchers commented.

A winning combination

When it came to lifestyle factors that affected weight, here’s what the researchers found:

• Increasing physical activity was associated with less weight gain.
• Increasing alcohol intake was linked to weight gain.
• Sleeping for less than six, or more than eight, hours per night was associated with greater weight gain.
• Spending more time watching television was linked to greater weight gain.
• Quitting smoking resulted in some weight gain initially, but the amount lessened in the years after quitting.

So, here’s the checklist that may help you maintain a healthy weight as you age:

• Eat more whole grains, vegetables, nuts, and yogurt.
• Eat less potatoes, red meat, sugar, and refined grains.
• Exercise more.
• Drink less alcohol.
• Get six to eight hours of sleep each night.
• Watch less television.

(N Engl J Med 2011;364:2392404.)