Diets low in fat and saturated fat can actually increase your risk of heart disease. But a high fat diet isn't necessarily the solution either.
The recently released Dietary Guidelines for Americans continue to stress the importance of limiting saturated fat. The primary charge against saturated fat is that it increases your cholesterol levels, which presumably raises your heart disease risk. But a meta-analysis of 21 studies involving more than a quarter of a million people shows that the amount of saturated fat you consume has no significant influence on your heart disease risk. What's more, three-quarters of the people who end up in the hospital due to heart attacks have normal cholesterol.
Clearly, old assumptions about saturated fat, cholesterol levels, and heart disease risk need to be updated. In fact, new research suggests that saturated fat may actually play a role in reducing your risk of heart disease.
Beyond "Good" and "Bad" Cholesterol
We've all been taught to think of cholesterol as being either "good" or "bad." HDL cholesterol is the "good" kind of cholesterol. The more HDL in your blood, the better. But the blanket categorization of LDL as "bad" cholesterol is an over-simplification. It turns out that LDL cholesterol particles come in different sizes—and the size and shape of your LDL particles may be even more important than how many you have.
If most of your LDL particles are big and fluffy, you may have a lower risk of cardiovascular disease. LDL particles that are small and dense, on the other hand, are associated with a higher risk. So, someone with high LDL cholesterol numbers but lots of big, fluffy particles may be better off than someone who has low LDL cholesterol levels but a lot of small dense particles. And this may explain the paradox of why so many people having heart attacks actually have low or normal cholesterol levels.
How Diet Affects Your Cholesterol Particle Size
This new understanding of cholesterol particle size also changes how we think about the relationship between saturated fat and heart disease risk.