I started my career as a medical reporter. During that time, I learned a lot about research–especially how to evaluate whether or not a study holds merit. For example, retrospective studies are less reliable than prospective studies, because it’s easy for researchers to look back at history through the lens of the hypothesis they want to prove, biasing the results. I learned that double-blind, placebo-controlled studies are considered the most accurate because they prevent the researcher from knowing which study subjects are in which group–another way to prevent bias.
I also learned that studies whose results are bought and paid for are highly suspect.
Last September, news surfaced about one particularly shady study that misdirected science for decades, and may have killed thousands of people as a result. I’m referring here to the recently uncovered “Project 226,” wherein the Sugar Association paid Harvard researchers today’s equivalent of $48,900 to publish study results concluding that reducing cholesterol and saturated fat were the only dietary interventions needed to prevent heart disease. The researchers “overstated” the role that fat played, while downplaying evidence implicating sugar as a cause of heart disease.
After those results were published in the New England Journal of Medicine in 1967, nutrition scientists and health officials became obsessed with reducing saturated fat, not sugar, to prevent heart disease. Who knows how many thousands of people died because they followed their well-meaning physicians’ recommendations to lower fat intake, happily munching away on high-sugar, low-fat foods all the way to the grave?
Because people are so attached to the “truths” that have become ingrained in them, it’s hard for them to shift their beliefs to truer truths. We’re still in that zone of “trust lag,” which is why your doctor still probably hasn’t given you the great news about steak yet. We’re so used to vilifying cholesterol and fat, we’re afraid to change.
But I’m here to tell you that it’s time to relax and break out the butter. Three of the largest, most comprehensive studies have recently blown the connection between saturated fat and heart disease out of the water.
In 2014, a massive review of 76 studies with a total of over 650,000 participants found no link between saturated fat consumption and the risk of heart disease or death. Last year, in a study that followed 59,000 people, researchers found no statistically significant effects of reducing saturated fat, in regard to heart attacks, strokes, or all-cause deaths. Another 2015 review of 73 studies, with 90,500–339,000 participants in each, concluded that saturated fat intake was not linked to heart disease, stroke, type 2 diabetes, or dying of any cause.
By now you may convinced that saturated fat isn’t the killer you may have thought it was. But it goes beyond that:
- Fat increases satiety, keeping you fuller longer than high-carb or high-protein/low-fat foods do. So eating fat may actually help you keep calories down–useful if you’re trying to lose weight.
- Calories are a zero-sum game. Eating less fat usually means eating more carbs. And carbs are heavily implicated in the development of diabetes and insulin resistance, both of which are associated with heart disease and increased risk of death.
- Some fat is necessary to burn fat. Too little fat may convince your body that this macronutrient is scarce, so it may conserve stored body fat, just in case.
The number-one reason to start eating fat again? Bacon.