If you’re a meat and potatoes person, then you may want to rethink what you’re eating. That’s because with each additional serving of these foods, you’re likely to gain several pounds in just a few years, according to a new study published in The New England Journal of Medicine.
The problem for most adults is that their weight creeps up over time. By the time their kids enter college, most parents have gained upwards of 20 pounds. The question is how does this happen?
To answer this vexing problem, researchers at Harvard School of Public Health tracked the diet and lifestyle of over 120,000 health care professionals involved in three prospective studies (Nurses’ Health Study, Nurses’ Health Study II and Health Professionals Follow-up Study). By examining their habits at four year intervals for up to 20 years, researchers gained a better understanding of the dietary and lifestyle factors associated with weight gain.
To start, researchers found that on average study participants gained 3.35 pounds or 2.4% of body weight during each 4 year period. That doesn’t sound like much but this equates to a 16.8 pound weight gain over a period of 20 years.
When the diets of participants were further analyzed, researchers found that certain foods were more likely to cause weight gain while others promoted weight loss.
The five foods associated with the greatest weight gain (how many pounds people gained on average over 4 years):
- French Fries: 3.35 pounds
- Potato Chips: 1.69 pounds
- Boiled, Baked or Mashed Potatoes: 0.57 pounds
- Sugar-sweetened Beverages: 1.00 pound
- Unprocessed Red Meats: 0.95 pounds
The five foods associated with the greatest weight loss (how many pounds people lost on average over 4 years):
- Yogurt: -0.82 pounds
- Nuts: -0.57 pounds
- Fruits: -0.49 pounds
- Vegetables: -0.22 pounds
- Whole Grains: -0.37 pounds
Researchers also examined lifestyle factors such as physical activity, amount of sleep, time spent watching television, alcohol and tobacco use. Not surprisingly, those who exercised the most gained 1.76 fewer pounds in each 4 year period. Sleep also affected weight with those who slept fewer than 6 hours or more than 8 hours, having greater weight gain over time. Former smokers who started smoking again lost about 2.8 pounds but those who quit, gained about 5.2 pounds.
The strong positive association with weight change seen for starches, refined grains and processed foods is consistent with other shorter studies. With their lower fiber, healthy fat and protein content, consumption of refined grains and starchy foods are less satiating than fruits, vegetables and whole grains.
Researchers were somewhat puzzled by the association of less weight gain with yogurt consumption. Other studies have shown that the beneficial bacteria residing in the digestive tract differs in obese individuals. They theorized that regular consumption of yogurt, which includes probiotic bacteria, may help in weight control. Of course, regular yogurt eaters may also engage in other healthy lifestyle factors that were not uncovered in the study.
For dieters looking for simple answers, this study might seem confusing with mixed messages. For example, no significant differences in weight gain were seen for low-fat and skim milk versus whole-fat milk and the consumption of nuts was inversely associated with weight gain. The study points out the weakness in focusing on simply total calories, or fat grams or grams of carbohydrates.
“The message here is that the type and quality of food and beverage one eats are incredibly important,” says researcher Dariush Mozaffarian, M.D.
The Bottom Line
We all know how difficult it is to lose weight. For this reason, any adjustment you can make that prevents weight gain in the first place is extremely helpful. Perhaps easier said than done.
The morale of the study (or story) is that it doesn’t take that many calories to shift the balance in or out of your favor. But, by being aware of the foods that can easily add or help shed pounds over time, you can make more informed choices.
If you or your family love potato chips or French fries (and who doesn’t?) that’s ok. You just can’t eat them all the time. You may want to adopt the strategy of our household. My husband and I enjoy pizza, but we don’t eat it once a week. On occasion, we visit a local restaurant downtown and get our fix of Greek salad and pesto pizza. We thoroughly enjoy our meal but don’t visit again for another 6 weeks!
David H. Rahm, M.D. is the founder and medical director of The Wellness Center, a medical clinic located in Long Beach, CA. Dr. Rahm is also president and medical director of VitaMedica. Dr. Rahm is one of a select group of conventional medical doctors who have education and expertise in functional medicine and nutritional science. Over the past 20 years, Dr. Rahm has published articles in the plastic surgery literature and educated physicians about the importance of good peri-operative nutrition.