We’ve long known that “bad” fats aren’t the healthiest choices in our diets, but the latest news from Harvard is lethal: Eating too much saturated or trans fat can increase your risk of dying.
The silver lining? You can reverse some of that risk by making healthier fat choices.
“This study is by far the most detailed and powerful examination of the relationship between different types of dietary fats and mortality,” said Dr. Frank B. Hu, professor of nutrition and epidemiology at the Harvard T. H. Chan School of Public Health. “Our study demonstrates that not all fats are created equal, and eating healthy unsaturated fats at the expense of unhealthy saturated and trans fats is an important way to live a longer and healthier life.”
Hu and his fellow researchers analyzed the eating habits of more than 126,000 men and women over a 32-year period from 1980 to 2012, checking in with each participant every two to four years about the amount and type of fat in their diets.
All of the people in the study started off with no signs of cancer, type 1 or 2 diabetes, or cardiovascular disease. In each questionnaire, participants were asked how often they consumed portions of up to 150 types of fatty foods, as well as the types of margarine, fat or oil they used to prepare dishes. The researchers then compared those results against death rates.
Hu and his colleagues found that although eating more saturated fat and trans fats was associated with an increase in mortality, eating more polyunsaturated and monounsaturated fats lowered the risk of death. In fact, the study found that if people replaced a mere 5% of their calorie intake from “bad” fats with polyunsaturated fats, they could reduce their risk of death by 27%. If those calories came from monounsaturated fats, the risk of mortality dropped by 13%.
Why weren’t monounsaturated fats as protective? Perhaps the two good fats have different biological effects, Hu said. Or perhaps it’s the American diet.