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Intermittent Fasting and Metabolic Syndrome: The Facts

by Rahul Kapur

Intermittent Fasting and Metabolic Syndrome: The Facts

In recent times, the dietary practice of fasting has gained popularity and interest among scientists, health enthusiasts, and the mainstream. Fasting as a practice has been around since early human civilization, and recent studies show that it can have lasting effects on human health. Specifically, the practice of intermittent fasting, the voluntary abstinence from food and drink for periods at a time, is showing promising results for weight loss and improving health (1). One condition, in particular, that intermittent fasting may help with is metabolic syndrome. Although there are many risk factors for metabolic syndrome, studies have shown that intermittent fasting can offer a way to lessen this disease.

To understand how intermittent fasting can affect metabolic syndrome, it is important to understand what metabolic syndrome is and what causes it. Metabolic syndrome is a very complicated disease that can have many risk factors. Traditionally, it must include at least three of the five following:

  • Central obesity
  • High blood pressure
  • High blood sugar
  • High serum triglycerides
  • Low serum high-density lipoprotein (HDL)

Those with this condition are at a higher risk of developing cardiovascular disease and type 2 diabetes mellitus (DM) (2). Although the risk factors are many, the cause of this disease is still an area of research.

The easiest way to understand how intermittent fasting can affect metabolic syndrome is to consider how intermittent fasting can affect each of the five disease criteria.

Central Obesity

Central obesity, also known as visceral fat, is the most important sign of metabolic syndrome (2). By definition, visceral fat is fat stored inside the abdominal cavity around major organs such as the liver, kidneys, stomach, and pancreas. A sign of increased visceral fat is a large belly and waist. Too much visceral fat can increase the risk of type 2 DM, heart disease, insulin resistance, hypertension, breast cancer, colorectal cancer, and Alzheimer’s disease. It can also lead to other signs of metabolic syndrome and many scientists consider treating it a priority when treating the disease.

Intermittent fasting, according to recent studies, can help decrease visceral fat. One study done in 2014 showed that participants on an intermittent fast diet decreased their visceral fat percentage by 4-7% over 6-24 weeks. This is a significant finding considering that one percentage point can make a difference between high and low risk. Another study showed a decrease in visceral fat by fasting and calorie restriction 1 day out of the week for approximately 10 weeks (3). A solid link between intermittent fasting and visceral fat loss requires more studies, but initial results show promise.

High Blood Pressure

According to the American Medical Association the definition of high blood pressure, or hypertension, is blood pressure equal to or greater than 130/85 or medication use for elevated blood pressure. Elevated blood pressure can lead to heart failure, stroke, vision loss, and other serious health problems. 

Intermittent fasting can lower high blood pressure according to a study by the University of Surrey. Scientists asked overweight volunteers to attempt the 5:2 intermittent fasting diet for about two months. This diet instructs practitioners to eat normally five days out of the week, and on the remaining two days restrict their calorie intake. Here, volunteers ate only 600 calories on fasting days. The study found that participants achieved a 9% reduction in systolic blood pressure. All but one of those who had prehypertension (120–139/80–89 mmHg) and hypertension achieved normal blood pressure at the end of the study (4).

High Blood Sugar

High blood sugars or blood glucose levels are usually found in those with diabetes mellitus or can lead to symptoms of diabetes mellitus. These symptoms may include increased hunger, increased thirst, increased volume of urination, blurry vision, fatigue, dry mouth, seizures, coma, and even death.

The University of Adelaide reported that intermittent fasting can help blood glucose levels return to normal in people at risk for type 2 diabetes. They studied 15 men at risk for type 2 DM for 14 days as each participant underwent a time-restricted diet regimen. A time-restricted diet is a form of intermittent fasting in which participants consume foods only at specific times of the day.

During the study, volunteers were to follow their usual diets but limit their intake to a nine-hour time period. After monitoring glucose continuously, the results showed that glucose control improved among all participants regardless of what they ate. While promising, a larger study conducted over a longer period will provide more accurate information on the relationship between intermittent fasting and lowering blood glucose levels (6).

High triglycerides & Low serum high-density lipoprotein (HDL)

Cholesterol is a necessary molecule for all animals, as it has many important functions in the body. However, some cholesterol in excess, such as LDL cholesterol, can lead to problems such as coronary artery disease and even stroke. HDL cholesterol, considered healthy cholesterol, helps with the clearance of the less healthy LDL cholesterol from the blood. Excess triglycerides can cause coronary artery disease, pancreatitis, and liver problems.

Studies show that intermittent fasting can reduce cholesterol levels by approximately 20%. LDL levels also decreased by as much as 25% and so did small LDL particles, which can get stuck in blood vessels in the heart leading to heart attacks. Studies also show a 32% decrease in triglycerides by intermittent fasting. Fortunately, the tests did not show a significant decrease in HDL levels (7).

Metabolic syndrome is a devastating illness considering each of the conditions that make it up can lead to serious health problems on their own. It is important to understand how to treat this disease and intermittent fasting shows promise. However, it is hard to say with authority that intermittent fasting is a treatment for metabolic syndrome without more long-term studies. Some critics state that intermittent fasting is not for everyone, as those with problems regulating blood glucose do worse with fasting. They attribute this to increases in the stress hormone cortisol during fasting, which raises glucose levels. Regardless, metabolic syndrome is a difficult disease to handle, and if intermittent fasting offers even a little benefit, those affected should consider trying it.


  1. Tello, Monique. “Intermittent Fasting: Surprising Update.” Harvard Health Blog, 26 June 2018,www.health.harvard.edu/blog/intermittent-fasting-surprising-update-2018062914156.
  2. “Metabolic Syndrome.” Wikipedia, Wikimedia Foundation, 18 Apr. 2019, en.wikipedia.org/wiki/Metabolic_syndrome.
  3. Ryan, Raman. “How to Get Rid of Visceral Fat.” Healthline, Healthline Media, 22 Aug. 2017, www.healthline.com/nutrition/lose-visceral-fat#section13.
  4. Brewer, Sarah. “Intermittent Fasting Lowers Blood Pressure.” Lower Your Blood Pressure Fast, Lower Your Blood Pressure Fast, 24 Oct. 2018, www.mylowerbloodpressure.com/intermittent-fasting-lowers-blood-pressure?cn-reloaded=1.
  5. “Hyperglycemia.” Wikipedia, Wikimedia Foundation, 12 Apr. 2019, en.wikipedia.org/wiki/Hyperglycemia.
  6. Robertson, Sally. “Intermittent Fasting Shown to Improve Blood Glucose Levels.” News, 30 Apr. 2019, www.news-medical.net/news/20190430/Intermittent-fasting-shown-to-improve-blood-glucose-levels.aspx.
  7. Nett, Amy. “Could You Benefit From Intermittent Fasting?” Chris Kresser, Chriskresser.com, 22 May 2019, www.chriskresser.com/could-you-benefit-from-intermittent-fasting/.

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Rahul Kapur
Rahul Kapur