Year-long diet study finds it's what you eat, not how much

A UW Medicine dietitian comments on Stanford University research showing that neither low-fat or low-carb diets were key to sustained weight loss. Instead, it's back to basics: avoid refined wheat and sugar, and eat more vegetables. 

The old bromide “you are what you eat,” is true, but not quite the way nutritionists first thought.

A new study by Stanford University  published in JAMA has shown that it’s the quality of what you eat -– such as emphasizing whole foods and vegetables -– not quantity, which truly impacts the amount of weight one loses. Originally, the study set out to look at which diet might be better – either low-carb or low-fat -–  and whether diet success correlated to other factors.

“For decades we pursued the low-fat diet as the public health message,” said lead author Dr. Christopher Gardner, of Stanford University. “And then all the sudden there was a flip flop, and a low-carb diet was supposed to be the healthiest.”

The study found that those who cut back on refined sugars and wheat and loaded up on vegetables and whole foodsm without regards to portions or exercise, lost a significant amount of weight. This strategy worked, regardless of whether the study participants were in the low-fat or low-carb camps, or whether they had possible insulin resistance or genetic markers.

Judy Simon, a UW Medicine dietician who has followed Gardner’s work and was familiar with the study, said the results were encouraging and made a certain amount of intuitive sense.

“When people go on diets, 90 percent of the time, they gain the weight back,” said Simon. “But this seemed to be a program that was sustainable.”

The 600  participants in the study,which did not have a control group, were encouraged to find their own set points, she added.

“I think one of the main messages is that you need to focus on quality more,” she said.

On average, both groups lost on average between 11 to 13 pounds over the year, although some people lost as much as 60 pounds. The group was not asked to count or limit carbs, fats or calories. They weren’t asked to exercise.  They were asked to stay away from refined wheat products, such as white bread, crackers or pasta, and instead choose whole wheat, brown rice and legumes.The low-carb group was encouraged to eat avocados, nuts, olive oil or salmon. Participants were not asked to stay within a set number of calories, but to eat until they felt full.

 “I guess the main message is that you didn’t have to go on a ridiculously restrictive diet to get results,” Simon said.

Gardner added that study participants were encouraged not to eat in front of the TV.  They were asked to dine with family, prepare their meals at home, and to eat as many vegetables as possible.

What are your favorite vegetables?  Vote at UW Medicine's March Veggie Madness.

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