Does Fasting Lower Cholesterol?

What is cholesterol?

Cholesterol is a fat-like substance produced by the liver and is also found in some foods. There are two key types of cholesterol. 

The first is high-density lipoprotein (HDL) cholesterol. HDL is responsible for absorbing cholesterol and carrying it back to the liver, where it can be removed from the body. Because of this, HDL is commonly referred to as ‘good’ cholesterol. 

By contrast, low-density lipoprotein (LDL) is responsible for carrying cholesterol to cells. It can collect in the walls of your blood vessels, reducing the flow of blood and oxygen your body requires. This means that it is often labeled as ‘bad’ cholesterol. 

What is fasting?

Fasting is when you stop eating and drinking for a given period of time. It can be for a long or short duration, or it can be intermittent. Some people fast by restricting their caloric intake for two days a week. 

Not eating for 12 hours a day, 16 hours a day, or fasting every other day are some ways to fast. Essentially, the key idea is to restrict your intake for a prescribed period. 

Fasting has a long and convoluted history. It can be traced back to the 5th century to Hippocrates, who prescribed fasting to patients with acute fevers and diseases. Fasting also has many ties to different religious traditions.

Research is only now beginning to understand the benefits of fasting. 

The connection between fasting and cholesterol

What does fasting do to the body?

Fasting evokes drastic changes in cellular physiology and metabolism. It has been found to be highly beneficial for health. 

First, fasting can lead to drastic weight loss, particularly a loss of fat mass. It can also contribute to improved glycemic control and may protect the myocardium of the heart from inflammation. 

Some evidence has shown that fasting can delay aging by reducing oxidative stress and preserving memory. 

Some fasting regimens have been found to benefit the circadian rhythm, resulting in improved metabolic health and reducing the risk of chronic disease. 

How does it impact cholesterol?

In one study,¹ fasting regularly has been found to decrease bad LDL cholesterol.

Participants were required to fast for 12 hours during the day, three times a week, across a six-week period. In this study, it was found that fasting also increases your ‘good’ HDL cholesterol. 

The study only had 40 participants and only investigated one demographic (South Asian adults), so more research is required to see if these effects are replicated throughout the population. 

A review paper² in 2015 showed that alternate-day fasting trials lasting 3–12 weeks were highly effective at reducing total cholesterol (10–21%) and triglycerides (14–42%). 

Trials lasting 12–24 weeks were also effective, reducing total cholesterol by 5–20% and triglycerides by 17–50%. 

However, the studies in their review had different definitions of fasting, accounting for the variability of the results. In addition, the research so far has not demonstrated the optimal time period over which fasting should occur. 

How to check if cholesterol is lowered due to fasting

You can check your cholesterol levels through a blood test known as a lipid profile. This will be carried out following an overnight fast and involve drawing blood from a vein. 

The test is typically taken after overnight fasting because it allows variables to be minimized. It also helps to give a clearer picture of LDL cholesterol, as this needs to be calculated and can have distorted results if calculated after eating. 

The lipid profile will be able to inform you of your levels of HDL, LDL, triglycerides, total cholesterol, and your total cholesterol/HDL ratio. Knowing these results will help you to determine if you’re at risk of high cholesterol and provide a picture of your overall health. 

To see the impacts of long-term fasting on your cholesterol, you can get a lipid profile carried out to get a baseline picture before you start making any changes to your eating habits. Then, after following a fasting regimen for an extended period, you can have another lipid profile test carried out. This will enable you to compare the results and see the direct effects of your fasting regimen. 

Potential risks of fasting

Fasting is not recommended in a few circumstances. If you have a history of disordered eating or are underweight, do not attempt fasting. If you are pregnant, breastfeeding, or taking certain medications for diabetes, you will need to take other steps to lower your cholesterol. 

Fasting can also be challenging to take on psychologically, for example, being placed in various social scenarios while trying to maintain your fast. 

We would recommend talking to your doctor first to see if fasting could work for you. You may want to start gradually to see how your body responds and see if you can fast in a sustainable and healthy way. 

How else to lower cholesterol through a diet

Fasting isn’t the only way to lower your cholesterol. There are many other dietary changes that you can make. You can reduce saturated fats and eliminate trans fats. Foods high in these fats are fried foods, baked goods, and fatty meats. 

Eating more fiber is great for lowering your cholesterol. Start with beans, broccoli, and plenty of whole grains. 

One study³ identified that soluble fiber from pectin, oats, and psyllium all had similar cholesterol-lowering effects, which means you can pick your favorite fiber source to add to your next meal.

You can also lower your cholesterol through what you drink by opting for low-sugar and low-fat options. Other foods to add to your weekly menu should be legumes, nuts, and avocados. 

You can also lower cholesterol by exercising more, quitting smoking, and reducing alcohol consumption. Exercise lowers cholesterol by stimulating the number of receptors for LDL in the liver to boost the removal of cholesterol from the body. 

Exercise also increases one of the receptors involved in cholesterol metabolism, allowing more LDL cholesterol to be transported to the liver. 

Alcohol doesn’t contain cholesterol, but it can still impact your cholesterol levels. This is because alcohol affects how the liver processes and stores cholesterol, leading to a rise in triglycerides and LDL cholesterol levels.

The lowdown

So far, preliminary evidence has shown that fasting can be highly beneficial to health and has the ability to lower cholesterol. Fasting might be something you want to discuss next time you see your doctor.

It’s important to remember that fasting isn’t for everyone, and you should prioritize tailoring it carefully to your individual needs. If fasting isn’t an option for you, there are also many other potential steps you can take to lower your cholesterol and boost your overall health.