The Health Benefits of Intermittent Fasting
Intermittent fasting is an eating plan that switches between fasting and eating on a regular schedule. It doesn’t specify which foods you should eat but rather when you should eat them.
There are several different ways to intermittent fast, but they are all based on choosing regular time periods to eat and fast. Some popular approaches to intermittent fasting include:
- 5:2 Diet: Eat a normal diet five days a week and fast two days a week.
- Alternate-Day Fasting: Eat a normal diet one day and either completely fast or have one small meal (less than 500 calories) the next day.
- Daily Time-Restricted Fasting: Eat normally but only within an eight-hour window each day. For example, skip breakfast but eat lunch around noon and dinner by 8 pm.
Drinking water, coffee, tea and other non-caloric beverages are fine during periods of fasting.
Benefits of Intermittent Fasting
Many studies have been done on intermittent fasting. These studies have shown that it can have powerful benefits for weight control and the health of your body and brain. It may even help you live longer.
Here are the main health benefits of intermittent fasting:
- Weight Loss: Losing weight and being physically active help lower your risk of obesity-related diseases, such as diabetes, sleep apnea and some types of cancer. For these diseases, intermittent fasting seems to be about as beneficial as any other type of diet that reduces overall calories. Additionally, short term intermittent fasting changes hormone levels to slightly boost metabolism and facilitate weight loss.
- Insulin resistance: Intermittent fasting can reduce insulin resistance, lowering blood sugar, which should protect against type 2 diabetes.
- Reduced Inflammation: Some research suggests that intermittent fasting may be more beneficial than other diets for reducing inflammation and improving conditions associated with inflammation, such as arthritis, asthma, and stroke to name a few.
- Heart Health: Intermittent fasting may reduce “bad” LDL cholesterol, blood triglycerides, inflammatory markers, blood sugar and insulin resistance — all risk factors for heart disease.
- Brain Health: By increasing brain hormones that aid in the growth of new nerve cells, intermittent fasting may improve mental sharpness. It may also protect against Alzheimer’s disease.
Keep in mind that research on intermittent fasting is still in its early stages. Little long-term research has been done on intermittent fasting to examine how it affects people over time. As a result, long-term health benefits or risks are unknown.
Side Effects of Intermittent Fasting
It's important to note that intermittent fasting can have unpleasant side effects, but they usually go away within a month. Side effects may include:
- Hunger
- Fatigue
- Insomnia
- Nausea
- Headaches
Is Intermittent Fasting Right for You?
While intermittent fasting is safe for many people, it is not for everyone. Sticking with an intermittent fasting routine can be easier for some people rather than trying to watch calories every day. Other people, especially those with busy or variable schedules, have more difficulty maintaining an intermittent fasting routine. People who are underweight or have a history of eating disorders should not fast.
Intermittent fasting may have different effects on different people. For example, skipping meals may not be the best way to manage your weight if you're pregnant or breast-feeding. Before embarking on an intermittent fasting program, it’s important to work with your doctor and or a nutritionist who can take a look at your current medical conditions and best determine if intermittent fasting is appropriate for you.
People with certain medical conditions such as kidney stones, gastroesophageal reflux, diabetes or others should not fast without consulting with a doctor first. It is also important to talk to your doctor if you start experiencing unusual anxiety, headaches, nausea or other symptoms after you start intermittent fasting.
At the end of the day, there is no one-size-fits-all solution when it comes to nutrition. The best diet for you is the one that is safe you and one you can stick to in the long run to gain the most health benefits. If you feel good when fasting and find it to be a sustainable way of eating, it can be a very powerful tool to lose weight and improve your health.
References
Anton SD, Moehl K, Donahoo WT, et al. Flipping the metabolic switch: understanding and applying the health benefits of fasting. Obesity (Silver Spring) 2018;26:254-268.
Cioffi I, et al. Intermittent versus continuous energy restriction on weight loss and cardiometabolic outcomes: A systematic review and meta-analysis of randomized controlled trials. Journal of Translational Medicine. 2018; doi:10.1186/s12967-018-1748-4.
De Cabo R and Mattson MP. Effects of intermittent fasting on health, aging, and disease. New England Journal of Medicine. 2019;381(26):2541-2551. doi: 10.1056/NEJMra1905136.
Gordon B. What is intermittent fasting? Academy of Nutrition and Dietetics. https://www.eatright.org/health/weight-loss/fad-diets/what-is-intermittent-fasting. Accessed June 20, 2022.
Gunnars K. Intermittent Fasting 101 — The Ultimate Beginner’s Guide. Healthline. https://www.healthline.com/nutrition/intermittent-fasting-guide. Accessed July 14, 2022.
Mattson MP, et al. Impact of intermittent fasting on health and disease processes. Ageing Research Reviews. 2017; doi:10.1016/j.arr.2016.10.005.
Patterson RE, et al. Metabolic effects of intermittent fasting. Annual Review of Nutrition. 2017; doi:10.1146/annurev-nutr-071816-064634.
Phillips MCL. Fasting as a therapy in neurological disease. Nutrients. 2019; doi:10.3390/nu11102501.
Redman LM, Smith SR, Burton JH, Martin CK, Il’yasova D, Ravussin E. Metabolic slowing and reduced oxidative damage with sustained caloric restriction support the rate of living and oxidative damage theories of aging. Cell Metab 2018;27(4):805.e4-815.e4.
Research on intermittent fasting shows health benefits. National Institute on Aging. https://www.nia.nih.gov/news/research-intermittent-fasting-shows-health-benefits. Accessed June 20, 2022.
