With studies suggesting fasting may boost health, promote longevity and keep those extra pounds at bay, registered nutritionist Kerry Torrens takes a look at the science behind the claims and how fasting might fit in to our modern lifestyles.


What is fasting?

Fasting involves the abstinence from all or some food and drink for a given period of time. Despite being popularised by today’s diet world, the practice of fasting dates back centuries and is thought to be one of the oldest therapies in medicine. It plays a central role in cultural and religious practices, with all major religions partaking in one form or another.

Whether it involves the abstinence of food and drink or a lighter, lower-calorie form of eating, many argue that going without food for periods of time is something we have evolved to do.

Discover our full range of health benefit guides and learn more about different types of fasting, such as the 5:2 diet, intermittent fasting and the fast 800 diet.

Top 5 health benefits of fasting

1. Supports blood sugar management

Several studies support the use of fasting as a means of improving blood sugar control and potentially reducing the risk of diabetes, although gender may play a part and more studies are needed.

2. May help disease prevention

Lightening your normal eating pattern appears to give your body the time to focus on other important functions, including disease prevention. With this in mind, it may also improve the body’s ability to manage chronic inflammation and, as such, reduce the risk of conditions such as heart disease, multiple sclerosis and rheumatoid arthritis.

3. May support brain function

Studies in animals suggest fasting may protect against and improve outcomes in Parkinson’s and Alzheimer’s, as well as improve brain function by supporting memory and brain processing. Similarly, animal studies suggest fasting may protect brain health and increase the production of nerve cells.

Human studies report fasting may reduce symptoms of anxiety and depression and improve social connection.

More studies are needed to assess these effects but findings to date are encouraging.

4. May delay ageing and support growth and metabolism

Fasting, and in particular adopting a diet low in protein, has in animal studies been associated with an extended life expectancy.

Furthermore, fasting appears to promote levels of human growth hormone, a hormone that plays an important role in growth and repair, metabolism, weight loss, muscle strength and exercise performance.

Current longevity research is largely limited to animals, so more studies are needed to fully understand how this may impact human ageing.

5. May support weight loss

Many dieters turn to fasting as a manageable approach to weight loss. Studies show that controlling the times we eat or undertaking short-term fasts can aid weight reduction, fat loss and improve blood lipids. That’s not all: other studies have shown fasting to increase the ability to switch metabolism to fat burning, preserve muscle mass and improve body composition in overweight people.

Plate with a knife and fork and an alarm clock

Is fasting safe for everyone?

Fasting is not for everyone. It’s advisable to speak to your GP or healthcare professional before starting a new dietary regime, especially if you’re under 18, elderly, have a pre-existing medical condition (including diabetes and high blood pressure) or are on medication. Fasting isn’t recommended for people who are underweight, have an eating disorder or are pregnant or breast-feeding.

Please note: if you’re considering any form of diet, please consult your GP first to ensure you can do so without risk to your health.

Read more of our health guides:

What is the 5:2 diet?
What is an intermittent fasting diet?
What is the Fast 800 diet?
What is the Pioppi diet?
What is a ketogenic diet?

This article was reviewed on 16th November 2021 by Kerry Torrens.

Kerry Torrens is a qualified Nutritionist (MBANT) with a post graduate diploma in Personalised Nutrition & Nutritional Therapy. She is a member of the British Association for Nutrition and Lifestyle Medicine (BANT) and a member of the Guild of Food Writers. Over the last 15 years she has been a contributing author to a number of nutritional and cookery publications including BBC Good Food.

All health content on bbcgoodfood.com is provided for general information only, and should not be treated as a substitute for the medical advice of your own doctor or any other health care professional. If you have any concerns about your general health, you should contact your local health care provider. See our website terms and conditions for more information.


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