It’s no mystery that your waistline is influenced by how much food you eat, but the seemingly straightforward advice to “eat less and exercise more” is not so clear-cut when you compare the amount of calories found in a bag of potato chips to a bowl of vegetables.
Harvard School of Public Health researchers may just have the answers to what foods to avoid and what to eat more of for losing weight. In a study published in The New England Journal of Medicine, they documented the foods with the strongest associations for packing on weight or losing it.
The researchers combined data from diet and lifestyle questionnaires from 120,877 people—50,422 women from the Nurse’s Health Study, 47,898 women from the Nurse’s Health Study II, and 22,557 men from the Health Professionals Follow-Up Study. Over a 20-year period (from 1986 to 2006), the authors took body weight measurements every four years.
Consistent with the national trend, the average weight gain of the study participants was 3.35 pounds and 2.4 percent of body weight during each four-year period, which equated to a total weight gain of an average of 16.8 pounds at the conclusion of the study.
What foods had the strongest association with weight gain? These are the dietary tyrants with their contributions to average weight gain:
- Potato chips – 1.69 pounds gain
- Potatoes – 1.28 pounds gain (French fried potatoes contributed 3.35 pounds gain)
- Sugar-sweetened beverages – 1 pound gain
- Unprocessed red meats – 0.95 pounds gain
- Processed meats – 0.93 pounds gain
What foods had the least association with weight gain? Now that you know the culprits, it’s time to introduce the “good guys” with their contributions to average weight loss:
- Vegetables – 0.22 pounds loss
- Whole Grains – 0.37 pounds loss
- Fruits – 0.49 pounds loss
- Nuts – 0.57 pounds loss
- Yogurt – 0.87 pounds loss
The researchers also found that lifestyle factors such as time spent in front of the TV, sleeping fewer than six hours per night (not getting enough sleep can weaken our resolve to eat right!) or sleeping more than eight hours per night (likely due to higher amounts of inactivity) contributed to long-term weight gain.
The bottom line? Eating a poor diet and not exercising enough leads to a surplus in calories that increases body weight. What appears as small bad habits can cause us to pack on two decades worth of pounds, but, conversely, simply swapping out the sugary soda for low-fat dairy products can help put an end to weight gain.
While the “eat less, exercise more” mantra still applies, you should still focus on exercising the recommended 30 minutes daily three times a week and choosing lower-calorie, nutrient-dense foods that can keep you healthier longer.
Source: Mozaffarian D et al. Changes in Diet and Lifestyle and Long-Term Weight Gain in Women and Men. N Engl J Med 2011; 364(25): 2392-404.