Cholesterol has been widely vilified in the media, and to this day most doctors will warn you to keep your cholesterol levels low if you want to keep yourself out of an early grave.
This is one area where conventional wisdom — even among doctors — is not just years, but decades behind the research. In fact, for optimal health, fitness, and longevity, your cholesterol levels should be high.
How Much Fat and Cholesterol Does Your Body Need for Optimal Health?
You may know that there are three different “cholesterol levels” that you get tested for. These are differentiated by the transport molecules attached to cholesterol itself: low-density lipoproteins (LDL) and high-density lipoproteins (HDL).
LDL cholesterol, commonly called “bad cholesterol,” is a risk factor for heart disease. The reference range — that is, the “safe” value for LDL cholesterol — is usually set at less than 100 mg/dL. In general, the less, the better.
HDL cholesterol, a.k.a. “good” cholesterol, usually has a reference range of 40 or more mg/dL. In general, the thinking here is that more is better (not that it usually reaches much over 40).
Finally, there’s total cholesterol (TC). The reference range for this is usually set at under 200 mg/dL. The thinking here also tends to be that lower is better, but only up to a certain point, since total cholesterol includes both LDL and HDL cholesterol, as well as less common cholesterol types such as very-low-density lipoprotein cholesterol (VLDL).
So, conventional wisdom says that you want more HDL, less total cholesterol, and basically no LDL cholesterol if possible. But what does the research say?
The Research on Cholesterol
For starters, the research validates the conventional wisdom on HDL cholesterol: it’s beneficial. HDL carries cholesterol back to the liver for processing, which you do need, and more HDL is associated with positive health outcomes.
When it comes to total cholesterol, however, there is a U-shaped association between cholesterol levels and all-cause mortality. The lowest death rates are seen in people with mildly-elevated total cholesterol — in the 220 range. Cardiovascular mortality is lowest just below 200 mg/dl (but not much below), while cancer mortality is lowest in the range of 220-240 mg/dL.
As the authors summarize, The occurrence of a TC range of < 120 mg/dL was strongly predictive of heightened death risk from all causes, whereas a TC range of ≥ 280 mg/dL was not, except with regard to [cardiovascular disease] mortality.
Other studies agree that moderately-elevated cholesterol — relative to current standards — is actually ideal. According to Yi et al, TC levels associated with the lowest mortality were 210–249 mg/dL.
The Lowdown on LDL Cholesterol
What about LDL cholesterol specifically? Again, there’s a U-shaped relationship with all-cause mortality, and elevated values are ideal. The lowest all-cause mortality was seen in patients with LDL cholesterol levels of 130-159 mg/dL, followed by levels of 100-129.
Why is this, though? LDL transports cholesterol from the liver to other parts of the body, and as you might guess, that’s a necessary function. (Calling it bad cholesterol is, therefore, poorly misguided.)
It’s true that some of this cholesterol gets deposited into your blood vessels, which leads to arterial hardening — a risk factor for heart disease. However, some physicians have hypothesized that even this serves a positive function, at least in moderation. LDL cholesterol may act as a sport of “spackle,” fixing small cracks in your blood vessels before they become ruptures. Then again, the risk of heart disease may simply be a necessary evil, but the reality is that scientists aren’t really sure yet.
How Much Fat Should You Consume to Maintain Optimal Health?
The old low-fat diet dogma has been pretty well debunked at this point, but most people still aren’t clear on what fat is, or does.
Fat is divided into saturated, monounsaturated, and polyunsaturated fats. Saturated fat forms a straight chain, while unsaturated fats feature bends in the chain — one for monounsaturated, more for polyunsaturated.
Saturated fat is mostly found in animal products, with the main plant source being coconut oil. It increases your body’s own production of cholesterol, which we already know isn’t bad (at least up to a point).
Monounsaturated fat is largely found in nuts, eggs, avocados, olives, and olive and canola oils. Polyunsaturated fats are found in fish; most nut, seed, and vegetable oils; flaxseeds; and walnuts.
Some research also suggests that total fat — and saturated fat consumption in particular — increases testosterone, and monounsaturated fat consumption may as well. On the other hand, polyunsaturated fat intake is associated with having more muscle and less belly fat. Intake of omega-3 fat — a subtype of polyunsaturated fat mainly found in fish — is associated with a variety of health benefits, including muscle growth, faster metabolism, and reduced risk of cancer and heart disease.
There is less research on monounsaturated fats, but what we do have is also very positive. In addition to possibly raising testosterone, it is associated with leanness.
Overall, research suggests that you should eat at least 20% of your total caloric intake in the form of fat, and possibly 40% or more for optimal results. You don’t need to hyper-optimize the exact types of fat, but an even mix of saturated, poly-, and mono-unsaturated is probably best. (And you should definitely eat a few grams a day of omega-3s, either by eating fish or taking fish oil capsules.)
What About Cholesterol Consumption?
Quite a few studies have found that eating more cholesterol increases sex hormone production and availability of free testosterone, as well as muscle protein synthesis (MPS). Accordingly, switching to a meal plan that's low in cholesterol and saturated fat will lower testosterone levels in men.
It's clear that cholesterol isn’t evil and won’t necessarily directly cause heart disease, but your body can also produce its own cholesterol if you eat plenty of fat. It’s probably not worth obsessing over, but you should aim to eat 200-500 milligrams of cholesterol per day from the best sources of cholesterol, which are eggs and shellfish.
A hyper fixation on a correlation between cholesterol levels and heart disease rather than looking more broadly at associations between cholesterol and all causes of mortality has led to cholesterol guidelines that are much lower than optimal. Remember that your goal isn’t to not die prematurely of a heart attack — it’s to not die prematurely, period.