The “Potato Chip Study,” published today in the New England Journal of Medicine, found interesting links between certain foods and weight gain. Researches from Harvard University looked at the long-term effects of diet, exercise and other lifestyle changes in a study that included over 120,000 men and women.

4-year weight change was most strongly associated with these foods (average weight gain/loss is shown in parentheses):

  • potato chips (1.69 lb)
  • potatoes (1.28 lb) – of any kind such as baked, fried, mashed or boiled
  • sugar-sweetened beverages (1.00 lb)
  • unprocessed red meats (0.95 lb)
  • processed meats (0.95 lb)

So what’s so bad about potatoes? Looked at separately, French fries were linked with more than 3 lbs of weight gain alone. One hypothesis is that people who eat potato chips or french fries probably consume large quantities of other processed foods. I have a theory that what the potatoes are cooked in might be a factor. Most are sizzled in a bath of unhealthy goop such as partially or fully hydrogenated oils, cottonseed oil, and canola oil. Dr. Dariush Mozaffarian, the lead author of the study had this to say:

So why would potatoes be particularly fattening? It’s not clear. Maybe because they’re generally eaten in large quantities, Mozaffarian says, or possibly because, as some previous research has shown, they are the type of food that causes big spikes in blood sugar and insulin, which tends to make people hungrier and overeat at their next meal. Other starches and refined carbohydrates like white bread, white rice, low-fiber breakfast cereal, candy and desserts may affect the body the same way, he says. (On average, the study showed that foods that fell into the “refined grains” and “sweets and desserts” categories were associated with just under half-a-pound of weight gain.)

-Time Healthland

Within each 4-year period, participants gained an average of 3.35 lbs. It is important to note that the study relied on self-reported portion sizes of each food and only included white, educated adults. Also, there is no mention of the quality of food within each category. For example, there is a big distinction between a Big Mac and home-cooked, organic, grass-fed beef. These differences can be significant and are applicable for every food type listed here (both good and bad).

The study also looked at which foods were associated with less weight gain over the 4-year period. They included:

  • yogurt (−0.82 lb)
  • nuts (−0.57 lb)
  • fruits (−0.49 lb)
  • whole grains (−0.37 lb)
  • vegetables (−0.22 lb)

Yogurt is an interesting discovery. My guess is that it has something to do with all those live cultures helping our intestines do their job (learn a little more about good gut bacteria in this prior post). The other foods on the list are not surprising to me, but it is always a great reminder of what should consistently be on our plate at every meal.

The lifestyle factors associated with weight change included:

  • physical activity (−1.76 lbs)
  • alcohol use (0.41 lb per drink per day)
  • smoking (new quitters, 5.17 lb; former smokers, 0.14 lb)
  • sleep (more weight gain with <6 or >8 hours of sleep)
  • television watching (0.31 lb per hour per day)

Okay, this is not rocket science. We need ditch the junk food, get off our tushies, quit smoking, drink less, sleep more, and turn off the TV. Deep sigh. Oh how I love to stay up late sitting on the couch with a glass of syrah, watching So You Think You Can Dance. The quest to loose weight and keep it off is the equivalent to finding life on other planets. Both have fanatics claiming to know the truth, we’re pretty sure Area 51 and “weight nirvana” exists, but in the meantime, most of us are stuck with exceedingly busy lives, expanding waistlines and no time to find those elusive little green men aka: the ideal weight. This study probably won’t rock your world, but if it helps motivate you to make one very tiny change in your diet or lifestyle, my work here is done. Mango lassi anyone?

The New England Journal of Medicine
Time Healthland
Image: stevendepolo via Flickr