This week, a study published in The Lancet further fueled the controversy by strongly challenging the conventional wisdom that the less fat you eat, the better. By closely tracking the eating habits of more than 135,000 people from 18 countries, researchers found that on a global level, diets higher in fat (35 percent of daily calories) are linked to a 23 percent reduction in the overall risk of death compared to diets that are low in fat (11 percent of daily calories). They also found that a higher-fat diet reduced the risk of stroke — also considered a cardiovascular event — by 18 percent.
“Contrary to popular belief, increased consumption of dietary fats was associated with a lower risk of death,” said lead author Mahshid Dehghan, an investigator at McMaster University’s Population Health Research Institute, in an audio interview posted on The Lancet website. “The association with lower mortality was seen with all major types of fat,” she added, even saturated fat.
RELATED: The Guts of Hunter Gatherers Point the Way to Our Lost Microbial Diversity
The real danger, researchers discovered, is when people replaced dietary fats with large amounts of carbohydrates. According to study data, which included middle and low-income individuals living on five continents, more than half of the world gets 60 percent or more of their daily calories from carbohydrates, and a quarter gets more than 70 percent of their calories from carbs.
While high-fat diets failed to predict mortality, high-carb diets proved to be a killer. Diets where 60 percent or more of the daily calories came from carbs were associated with a 28 percent greater risk of death.
Before you run out and buy a “healthy” dinner of fried chicken and ice cream, it’s important to put the new study into perspective. One of the chief motivations for surveying such a large and diverse population was that most current dietary recommendations are based on Western diets. In general, North Americans and Europeans don’t struggle to eat enough fat. But the push to limit fat intake in the West doesn’t apply to places like China and Africa, where fat intake is low, but carbohydrate consumption is sky high.
"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,” said Dehghan in a statement, emphasizing that dietary recommendations need to be tailored for specific communities. For much of the world’s populations that means cutting back on carbs and beefing up on fats.
Current global dietary guidelines recommend that 55-65 percent of daily calories come from carbohydrates and less than 10 percent should come from saturated fat, but again, those numbers were based on studies performed in North America and Europe. The new global data showed that very low saturated fat intake (less than three percent) was much worse for people than a diet where 13 percent of calories come from saturated fat.
RELATED: How Eating Releases Opioids in the Human Brain
Dehghan and her team recommended a diet that’s 50-55 percent carbs and 35 percent fat, including both saturated and unsaturated fats. The researchers agreed that trans fats, the “hydrogenated” vegetable fats found in some packaged snacks, should be eliminated completely.
“Our data provide evidence that moderation, as opposed to very low or very high intakes, in consumption of both fats and carbohydrates is preferred,” Dehghan said in her audio interview. “Researchers and policymakers should consider this new global evidence, which questions dietary guidelines and challenges the existing thinking on lowering fat to a very low level.”
Dehghan’s paper follows on the heels of another bombshell study based on lost data from the 1960s showing that replacing a diet rich in saturated fat with unsaturated vegetable fats not only doesn’t decrease the risk of heart disease, but it increases the risk of death by 22 percent.
Bring on the butter.
WATCH: Why Your Diet Isn't Working