Fasting and Cholesterol: What You Need to Know
How can I lower my cholesterol without taking medication? And what effect does intermittent fasting have on cholesterol?
High cholesterol is thought to be a treatable risk factor for cardiovascular disease, including heart attack and stroke. There are a lot of nuances about cholesterol, and I won’t go into them, but traditionally, the main categories are LDL or “bad” cholesterol and HDL or “good” cholesterol.
A study by Framingham Hart in the early 1960s determined that high cholesterol levels, as well as high triglyceride levels, were associated with heart disease. The correlation is much weaker than most people think, but the results are slightly better when LDL and HDL are considered separately. Because cholesterol is found in atherosclerotic plaques (blockages in the heart), the dilated blood vessels intuitively act as “clogged arteries.”
A low-fat, low-cholesterol diet
In some studies, very low-fat diets may slightly lower LDL (bad) cholesterol, but they also tend to lower HDL (good) cholesterol, so it’s doubtful that they improve overall health. Other studies have not shown such reductions. For example, here is a 1995 study in which 50 subjects were fed a diet containing 22% or 39% fat. Their baseline cholesterol was 173 mg/dL. After 50 days on the low-fat diet, it dropped to 173 mg/dL. Oh… Cholesterol doesn’t go up much on a high-fat diet. After 50 days on a high-fat diet, cholesterol rises slightly to 177 mg/dL.
Millions of people try low-fat and low-cholesterol diets without realizing that these diets have been proven to be ineffective. I hear this all the time. Every time someone tells me their cholesterol is high, I say, “I didn’t know that. They say, “I’ve eliminated all fatty foods.”. Well, cutting fat out of your diet doesn’t change your cholesterol. We’ve known that for a long time. At best, it’s a marginal change. So what should we do? Statins?
“A little hunger really does more for the average patient than the best drug or the best doctor” – Mark Twain.
Studies have shown that fasting is a simple way to eat that can significantly lower cholesterol levels.
Now, there’s a lot of controversy about blood lipids, and we don’t want to get too caught up in it. For example, there are many details about the calculation of particle size, total number of particles, new particles, etc. that are beyond the scope of this discussion. I will limit this discussion to classical HDL/LDL/ and triglycerides.
HDL (High-density lipoprotein)
The “good” cholesterol (HDL) has a protective effect, so the lower the HDL, the higher the risk of CV disease. This association is actually much stronger than the LDL association. These are only associations, HDL is only a marker for disease. Just like dying your hair doesn’t make you look younger, taking drugs that increase HDL doesn’t prevent heart disease.
A few years ago, Pfizer invested billions of dollars in researching a drug called Torcetrapib (a CETP inhibitor). This drug was able to significantly increase HDL levels; it could save lives if low HDL levels caused a heart attack. Pfizer was so confident that they spent billions of dollars to prove the effectiveness of this drug.
Studies were conducted. The results were staggering and breathtakingly ugly; the drug increased mortality by 25%, and like Ted Bundy left and right, several other drugs of the same type were tested, but with the same deadly effect. Another illustration of the truth: “Correlation is not causation.”
But we focus on LDL because it is a marker of disease, just as a fever is often an obvious sign of an underlying infection; if HDL is low, it may indicate that the underlying disease is also worsening. What happens to HDL during fasting? The graph shows that fasting for 70 days, every other day, has little effect on HDL levels; there is a decrease in HDL, but it is small.
The history of triglycerides (TG) is similar; TG is a marker of disease, but does not cause disease. Niacin is a drug that increases HDL and decreases TG, with little effect on LDL.
The AIM HIGH trial tested the cardiovascular benefits of niacin. The results were stunning. Surprisingly bad, in fact. If they don’t kill people, they don’t help them. And there were many side effects. So TG, like HDL, is just a marker, not a cause of disease.
What happens when I take TG on an empty stomach? Daily alternating fasting can significantly reduce TG (good) levels by up to 30%. In fact, triglyceride levels are quite sensitive to diet. However, this does not mean that you should reduce the fat and cholesterol in your diet. On the contrary, reducing carbohydrates seems to be the main factor in lowering TG levels.
LDL (Low-density lipoprotein)
What happens to your LDL levels when you fast? Well, they go up. Quite a bit; over the course of 70 days of alternating daily fasting, LDLs were reduced by about 25% (very good). While drugs can reduce them by about 50% or more, this simple dietary measure is almost half as potent as the most powerful class of drugs in use today.
When combined with weight loss, maintaining fat-free mass and reducing waist circumference, it is clear that fasting can produce very powerful improvements in these cardiac risk factors; not forgetting the reductions in LDL, triglycerides and HDL.
But why does a normal diet have no effect, while fasting does? Simply put, it’s because during fasting, your body switches from burning sugar to burning fat for energy. Free fatty acids (FFA) are oxidized to make energy and FFA synthesis is reduced (the body burns fat but does not make it). Triacylglycerol synthesis is reduced, leading to a decrease in VLDL (very low density lipoprotein) secretion by the liver, which lowers LDL.
The way to lower LDL is to let the body burn it. The mistake with a low-fat diet is that if you give your body carbohydrates instead of fat, it will not burn fat, only carbohydrates. The mistake of a low-carb, high-fat diet is that by giving your body a lot of fat, you’re actually burning fat, but you’re burning what’s going into your body (dietary fat). It doesn’t take the fat out of your body.
For those of you who have the whole picture, I won’t say much more, but here goes. Fasting has the following benefits.
- Reduces weight
- Maintains lean mass
- Decreases waist size
- Minimal change in HDL
- Dramatic reductions in TG
- Dramatic reductions in LDL
All of this is good because it means that I got the best possible results. I don’t know if these will lead to better heart results, but I don’t have the answer. I think it will.
But that’s the point of fasting. It has all the benefits. The risks are minimal. What are you going to lose (besides a few pounds)?
For those who fear a heart attack or stroke, the question is not “Why fast?” but rather, “Why not fast?” .