Intermittent fasting is the practice of eating for fewer hours of the day or alternating between feeding and fasting days. It is simple to learn, costs nothing to do, and makes dieting easier. But, does it produce results?
In this post, I share what science has to say about the benefits of intermittent fasting.
Fasting Benefits At-A-Glance
- Weight loss is enhanced through the increased release of metabolic hormones and increased metabolic flexibility.
- Blood sugar and insulin levels are controlled, which disrupts the progression of blood sugar disorders like diabetes.
- Inflammation is lowered, reducing damage to your heart, blood vessels, brain, and other organs.
- Fasting improves markers related to heart health including cholesterol, triglycerides, and blood pressure.
- Fasting improves autophagy, which is a housekeeping process that your body performs to clean up damaged cells and debris.
Intermittent Fasting – 5 Science-Based Benefits [Video]
In this video, you’ll learn…
- The many different ways that intermittent fasting benefits your health!
- Research on the ways we are affected by a shorter eating window.
- Practical tools to help you begin intermittent fasting.
One of the main reasons people practice intermittent fasting is for weight loss.
It does work; some of its success is attributed to the fact that reducing your eating window naturally lowers your calorie intake. It cuts out calorie-dense things like bedtime snacks and after-dinner drinks. Additionally, there are metabolic advantages that come from fasting.
Fasting also makes your body more metabolically flexible, meaning that your body becomes efficient at running on any readily available fuel.
In the body, the two main sources of fuel are glucose and fatty acids. These energy-rich molecules come in through your diet when you eat carbohydrates and dietary fats.
They are also stored in your body as glycogen or body fat. Glucose is easier for your body to burn than fat. To become a better fat burner, you need to deplete glucose. Fasting accomplishes this task.
When you fast, there is no glucose coming in from your diet, so it pulls glucose out of the glycogen stores. When those small storage sites run low, your body turns to the larger stores of energy found in your fat cells.
Blood Sugar Control
Many of today’s foods are highly refined carbohydrates – things like cereal, toast, sandwich bread, sugary drinks, pasta, and desserts. Most carbohydrates get broken down into glucose (a simple sugar) by your digestive tract.
If the carb-containing food has been refined, it digests and gets absorbed into your blood quickly, causing a sharp rise in your blood sugar level. The rise in blood sugar causes a rise in insulin. Eating every couple of hours, causes continual spikes that encourage weight gain. It also contributes to the onset of blood sugar disorders like prediabetes and diabetes. (3)
Intermittent fasting is a way of disrupting the progression of blood sugar disorders. With no food coming in, there is no rise in blood sugar or insulin.
One clinical study found that eating within a 10-hour window may help stave off diabetes by reducing Metabolic syndrome. Metabolic syndrome is a cluster of conditions, including chronically high blood sugar, high blood pressure, high triglycerides, increased belly fat, and low HDL cholesterol. (4)
When blood sugar and insulin are chronically high, it sets up a chronic state of inflammation in your body. Chronic inflammation is also caused by lifestyle factors, like smoking, obesity, and chronic stress. This prolonged state causes damage to your heart, blood vessels, brain, and other organs.
Fasting defends the body against inflammation. This positive effect may be enhanced if your fast is beginning early in the evening.
One study on women from the 2009–2010 National Health and Nutrition Examination Survey (NHANES), found that for each 10% increase in the proportion of calories eaten after 5 PM there was a 3% increase in inflammation. Starting your fast after eating an early dinner may help lower disease-causing inflammation in the body. (5)
Improved Heart Health
The inflammation-lowering effect that comes from intermittent fasting helps protect your heart and blood vessels from damage. There are other ways that fasting improves cardiovascular health.
There also is some evidence that fasting can improve blood pressure.
There are a number of studies that show that fasting is effective at reducing Metabolic syndrome. This effect, however, was not evident in all of the studies that looked at blood pressure. The lack of results may be attributed to the fact that many studies lasted a few weeks or months, which was not enough time for significant results to show.
Moving on, another benefit of intermittent fasting is that it helps your body clean house through a process called autophagy. Autophagy is a term that literally means self-eating. It is a necessary housekeeping chore that your body performs to remove damaged cells and debris.
Digesting food requires a lot of energy and resources. When you eat, your body does not have the time or energy to dedicate to autophagy. When you restrict food intake, your body has time and resources to spare, making intermittent fasting an important driver of autophagy. (8) (9)
Many people have started intermittent fasting for the weight loss benefits. Fasting also benefits your heart, boosts autophagy, and controls blood sugar and inflammation.
Finally, if you would like to try intermittent fasting, but you’re not sure how to start, here is a complete how-to guide that shares my recommendation on the best way to start, six common mistakes to avoid, and three ways to make fasting much easier.
Free Fasting Guide
(1) Zauner, Christian, et al. “Resting energy expenditure in short-term starvation is increased as a result of an increase in serum norepinephrine.” The American journal of clinical nutrition 71.6 (2000): 1511-1515.
(2) Ho, Klan Y., et al. “Fasting enhances growth hormone secretion and amplifies the complex rhythms of growth hormone secretion in man.” The Journal of clinical investigation 81.4 (1988): 968-975.
(3) Feinman, Richard D., et al. “Dietary carbohydrate restriction as the first approach in diabetes management: critical review and evidence base.” Nutrition 31.1 (2015): 1-13.
(4) Wilkinson, Michael J., et al. “Ten-Hour Time-Restricted Eating Reduces Weight, Blood Pressure, and Atherogenic Lipids in Patients with Metabolic Syndrome.” Cell Metabolism (2019).
(5) Marinac, Catherine R., et al. “Frequency and circadian timing of eating may influence biomarkers of inflammation and insulin resistance associated with breast cancer risk.” PloS one 10.8 (2015).
(6) Bhutani, Surabhi, et al. “Improvements in coronary heart disease risk indicators by alternate‐day fasting involve adipose tissue modulations.” Obesity 18.11 (2010): 2152-2159.
(7) Mattson, Mark P., Valter D. Longo, and Michelle Harvie. “Impact of intermittent fasting on health and disease processes.” Ageing research reviews 39 (2017): 46-58.
(8) Alirezaei, Mehrdad, et al. “Short-term fasting induces profound neuronal autophagy.” Autophagy 6.6 (2010): 702-710.
(9) Jamshed, Humaira, et al. “Early Time-Restricted Feeding Improves 24-Hour Glucose Levels and Affects Markers of the Circadian Clock, Aging, and Autophagy in Humans.” Nutrients 11.6 (2019): 1234.
About the Author:
Dr. Becky Gillaspy, DC graduated Summa Cum Laude with research honors from Palmer College of Chiropractic in 1991.