Huge Diet Study Shows Carbs, Not Fats Are the Problem
Written by Editor   
Thursday, September 07, 2017 05:08 PM

An enormous prospective study of food intake in adults challenges several staunchly held beliefs about dietary components and their association with health risks: finding, for example that diets rich in fats, including saturated fats, don’t increase mortality risk, but high-carbohydrate diets do.

And the study, called PURE (Prospective Urban Rural Epidemiology), also found that the benefits of fruits, vegetables, and legumes top out at just three to four total servings per day. In sum, the results suggest that nutritional guidelines and conventional wisdom regarding these basic dietary elements may be seriously mistaken.

PURE investigators recorded food intake using questionnaires in 135,000 people in 18 countries, including high-, medium- and low-income nations. PURE found that high carbohydrate intake was associated with a significant increase in the risk of death, while both total fat and saturated and unsaturated fats were associated with a decreased risk of death. However, fat consumption was not associated with cardiovascular disease or cardiovascular mortality, though saturated fat had an inverse association with stroke.

The authors found that high intake of carbohydrates had "the most adverse impact on cardiovascular risk factors" while monounsaturated fats had a beneficial effect and saturated fat had a neutral effect.

“Reducing saturated fatty acids and replacing them with carbohydrates might have an adverse effect on cardiovascular disease risk," they concluded. "Current recommendations to reduce total fat and saturated fatty acids in all populations, which de facto increases carbohydrate intake, are not supported by our data."

The study did confirm that fruits and veggies (and legumes) in moderation are good for you, but it did not show that the benefits keep growing with increased consumption. Instead, the PURE researchers found that the maximum benefit was achieved with three to four serving per day. Current guidelines recommend that people consume five servings a day. The authors note that many people in lower income countries are unable to afford this high level of consumption.

“Optimal health benefits can be achieved with a more modest level of consumption, an approach that is likely to be much more affordable," write the PURE investigators.

The current focus on promoting low-fat diets ignores the fact that most people's diets in low and middle income countries are very high in carbohydrates, which seem to be linked to worse health outcomes. In low- and middle-income countries, where diets sometimes consist of more than 65% of energy from carbohydrates, guidelines should refocus their attention towards reducing carbohydrate intake, instead of focusing on reducing fats. The best diets will include a balance of carbohydrates and fats – approximately 50-55% carbohydrates and around 35% total fat, including both saturated and unsaturated fats. "