Harvard Study Says Limiting Saturated Fat and Refined Carb Intake May Lower Heart Disease Risk

Researchers estimated that replacing just 5 percent of saturated fat calories with healthier foods could lower risk.

In the face of a study that says Americans are eating more full-fat foods than ever, new research from the Harvard School of Public Health (HSPH) says limiting saturated fat and refined carb intake is still a good way to prevent conditions such as heart disease.

Recommendations about fat consumption are notoriously fickle; low-fat, high-carb used to be the gold standard, but recent food crazes like the Paleo diet and Bulletproof Coffee have challenged that logic. HSPH’s researchers, however, found that cutting down on saturated fat, as well as refined carbohydrates, decreased individuals’ risk of developing coronary heart disease (CHD).

The researchers looked at health and diet information collected by two long-running studies, which cumulatively gave them access to the data of more than 120,000 people. At the start of the trials, none of the respondents had diabetes, heart conditions, or cancer; by the follow-up stage, 7,667 had developed CHD.

After examining the participants’ food diaries and health conditions recorded over four years, HSPH’s team estimated that replacing just 5 percent of daily calories from saturated fat with calories from polyunsaturated fats, monounsaturated fats, or whole grains lowered heart disease risk by as much as 25, 15, and 9 percent, respectively. Replacing calories with refined carbohydrates like pasta and white bread, however, did not alter CHD rates.

In a statement, co-first author Yanping Li says the findings prove that both high-fat and high-carb diets can be damaging:

“Our findings suggest that the low-fat, high-carb trends of the 1980s and 1990s are not effective in reducing risk of CHD. It means that individuals should not replace saturated fat with refined carbs or vice versa. Dietary recommendations to reduce saturated fats should specify their replacement with unsaturated fats or with healthy carbohydrates, such as whole grains.”

In other words, keep using common sense and step away from the butter knife.