"The types of fat in our diet are more important that the total amount of fat."

By Gillie Houston
Updated May 24, 2017
Ligurian Olive Oil Cake

It's no secret that "good fats" are, well, good for you. But a new study from Harvard University suggests that the benefit of eating healthy, unsaturated fats is greater than previously thought—and that eating too much saturated or trans fats could up your risk of mortality significantly.

"This study is by far the most detailed and powerful examination of the relationship between different types of dietary fats and mortality," writes study author Dr. Frank B. Hu, a professor of nutrition and epidemiology at the Harvard T. H. Chan School of Public Health.

According to Science Daily, Hu and his team or researchers found that replacing saturated fats like butter, lard, and red meat fat with unsaturated, plant-based fats like olive oil, canola oil, and soybean oil can result in substantial, possibly life-changing health benefits.

Over the course of the study, the researchers followed the eating habits of more than 126,000 men and women over a 32-year period, monitoring the types and amount of fat in their diets via questionnaires about 150 varieties of fatty foods. Every study participant had no signs of cancer, diabetes, or cardiovascular disease at the start. At the conclusion of the study period in 2012, Hu found that those who consumed more saturated and trans fat had a higher risk of mortality, while those who ate more unsaturated fats actually lowered their risk of death.

Researchers suggest that even replacing 5 percent of calorie intake from saturated fats with plant-based fats could reduce the risk of dying by a whopping 27 percent. While this study is at odds with other recent data that suggests butter isn't as bad for the body as previously thought, the study authors say that the consumption of ingredients containing higher amounts of saturated fat could increase the risk of cardiovascular disease, cancer, neurodegerative disease, and respiratory disease. Study participants who appeared to replace saturated fats with carbohydrates in their diets showed only a slightly lower risk of mortality.

"All fats are not created equal, and eating healthy unsaturated fats at the expense of unhealthy saturated fats and trans fats is an important way to live a longer and healthier life," Hu says. However, the study also points out that the source of the food could play a significant roll in the impact of both saturated and unsaturated fats on the body, and that more research is needed to make that distinction.

In a nutshell, Hu says that the major implication of the study is that "the types of fat in our diet are more important that the total amount of fat," backing up the new 2015-2020 Dietary Guidelines for Americans, which emphasizes the type of fat, rather than the quantity. To kick start a more risk-free lifestyle, Hu recommends replacing animal fats with liquid vegetables oils first and foremost. "There is still a long way to go to improve the quality of fats and the overall diet quality in the U.S. population," Hu says. The researchers at Harvard hope their findings will encourage some of that population to reverse the way they think about and consume fat.

Wondering how to get more olive oil into your diet? We have some suggestions.