Eating fat causes high cholesterol and heart disease, eating fat makes you fat, and a low-fat diet is healthy and prevents heart disease. These are deeply ingrained beliefs in society, commonly preached by large health organizations. But the truth is more complicated than that, and recent research suggests that these age-old nutrition norms may not hold up under scrutiny. Let’s dive into the real story on dietary fat.
Saturated fat doesn’t increase the risk of heart disease
A review of clinical trials published in the Nutrition Journal (2017) examined whether replacing saturated fat with polyunsaturated fat reduces coronary heart disease. The reviewers concluded that the evidence from randomized trials suggests that these dietary changes are unlikely to impact coronary heart disease events or affect death rates from heart disease. It’s worth noting that this contradicts earlier findings, which were based on inadequately controlled trials that the authors say reached inaccurate conclusions.
Similarly, a review of 41 observational studies published in the British Medical Journal (2015) found that saturated fat was not associated with a higher risk of all-cause death, death from heart disease, stroke, total heart disease risk, or risk of type 2 diabetes.
Eating a high-fat diet improves cholesterol levels
A randomized trial published in the European Journal of Clinical Nutrition (2017) provided participants with either a saturated fat or polyunsaturated fat-enriched diet, alongside omega-3 supplements. Both diets led to a reduction in cholesterol levels—a surprising result considering that most people believe eating high amounts of fat will increase cholesterol. Additionally, the study found that participants experienced a change in VLDL and LDL particle size, becoming larger and more buoyant. Although LDL is commonly referred to as “bad” cholesterol, it’s the smaller, denser particles that cause the most trouble.
Several other studies have demonstrated similar results, showing that eating a high-fat diet can have positive effects on cholesterol levels as opposed to increasing them.
Fat doesn’t make you fat
In a one-year trial, participants who followed a high-fat, low-carb diet lost 11.6 pounds and experienced a 1.3% decrease in body fat percentage. In contrast, those who followed a low-fat, high-carb diet lost only 3.9 pounds and had a 0.3% decrease in body fat. Another six-month trial in obese participants showed a 10.3-pound weight reduction in the high-fat group compared to a 4.8-pound loss in the low-fat group.
Numerous other studies have yielded similar results. Researchers believe that high fat intake improves satiety (feelings of fullness and satisfaction) and decreases overall caloric intake. Moreover, eating fat may provide certain metabolic advantages.
Although this analysis only scratches the surface of the research on dietary fat, it demonstrates that scientific findings often contradict widely accepted societal norms. Fat is an essential nutrient that our bodies need—even saturated fat. In understanding the different types of fat, we can make more informed decisions about what to include in our diets.
