What are the benefits of fasting?
Fasting means choosing certain times when you don’t eat. Many people use it as a simple way to manage their weight, feel more energetic, and support their overall health. In our latest article, we explore how fasting works, the benefits it can offer, and whether it might suit your lifestyle and health goals. You'll also learn how a simple at-home DNA test can give you personalised advice to support your weight management journey.
What is fasting?
Fasting is a planned period without calories, often repeated on a daily or weekly schedule. After about eight to twelve hours without food, the body uses up its quick-access sugar stores and starts to burn fat for energy. This process creates ketones (natural chemicals made when your body breaks down fat) that act as a steady fuel source for the brain and muscles. This shift, known as the "metabolic switch," is thought to be behind many of the health benefits seen with fasting.
Common types of fasting
Time-restricted eating (TRE)
With TRE you fit all of your day’s meals and drinks containing calories into a six- to ten-hour window and fast for the remaining hours. A popular pattern is 16:8 - say, eating between 10 a.m. and 6 p.m. and then having only water, black tea or black coffee until the next morning. The shortened window cuts late-night grazing and can improve insulin sensitivity, the hormone action that keeps blood sugar in a healthy range.
The 5:2 plan
On this plan, you eat your normal diet five days a week. On any two non-consecutive days you trim intake down to about 500 - 600 calories, split into one or two small meals. Because you still eat every day, many people find it easier to socialise and exercise, while the weekly calorie gap helps steady weight loss.
Alternate-day fasting (ADF)
ADF asks you to fast, or eat a very small 500-calorie meal, every other day. The next day you can eat freely. Research shows ADF often achieves bigger drops in belly fat and blood pressure than constant low-calorie dieting, but the full-day fast can feel challenging at first.
Religious fasts (e.g., Ramadan)
Ramadan involves fasting from dawn to sunset for a lunar month each year, with meals taken before sunrise and after sunset. When those meals remain balanced and portion-controlled, studies show improvements in cholesterol and triglycerides.
Five key benefits of fasting
Fasting can be a useful tool for many people, but it’s not just about skipping meals. Done properly, it can bring a range of benefits to both your body and daily routine.
1. Sustainable weight loss
Evidence shows that fasting can be a sustainable strategy for weight loss if individuals adhere to this properly and integrate it into their lifestyle.
2. Better blood sugar control
Fasting gives insulin (the hormone that locks sugar into cells) a rest. Over time, this rest makes insulin work better, lowers fasting sugar and can even support type 2 diabetes remission when supervised by a health professional.
3. Healthier heart numbers
Regular fasts lower “bad” LDL cholesterol, reduce blood fats called triglycerides and drop the top (systolic) blood-pressure reading, all of which cut heart-disease risk.
4. Steadier energy and fewer cravings
Once your body is used to burning fat, energy levels even out and sugar cravings ease because fuel arrives at a slow, steady pace rather than in sharp spikes.
5. Simpler eating routine
Fewer meals mean less planning, smaller food bills and far less mindless snacking, which makes it easier to stick to the plan long term.
Safe fasting tips for getting started
Fasting is safe for most healthy adults when done in a sensible and gradual way. These tips can help you get started without feeling overwhelmed or putting your body under stress.
- Begin gradually: Extend your usual overnight fast by one to two hours for a week before moving to longer gaps.
- Drink plenty: Aim for two to three litres of water a day. Black tea, coffee and herbal infusions are calorie-free options.
- Make protein the anchor of every meal: A palm-sized portion of chicken, fish, eggs, tofu or beans protects muscle and controls hunger.
- Fill half your plate with colourful plants: Vegetables, fruit and pulses provide fibre that keeps you full, feeds good gut bacteria and stabilises digestion.
- Include healthy fats: Avocado, olive oil, nuts and seeds add flavour, improve satisfaction and support heart health.
- Pause if you feel unwell: Headaches, dizziness or marked irritability are signals to break the fast, eat and reassess.
- Seek medical advice if you have health conditions: People with diabetes, low blood pressure, kidney or liver disease, or who are pregnant, breastfeeding or recovering from surgery should speak to a professional first.
DNA and weight management
Your body is unique, and your DNA holds clues about how it works. Some people naturally feel full sooner, store fat differently, or respond better to certain ways of eating. These differences can be influenced by your genes.
By looking at specific areas of your DNA, such as how your body handles hunger, fat storage, and your natural body clock (linked to melatonin), you can understand which weight management strategies may work best for you. This includes how your body might respond to different fasting schedules or meal timings.
MyHealthChecked’s Weight Management DNA Test can help you uncover these patterns. By knowing more about your own biology, you can make smarter, more confident decisions about when to eat, what to eat, and how to support your weight goals in a way that suits you best.
Role of at-home testing
MyHealthChecked’s Weight Management DNA Test is designed to help you understand how your body responds to food, exercise and fasting. With a simple cheek swab taken at home, the test analyses key genes linked to appetite, metabolism, fat storage, and your natural response to physical activity.
It also looks at how your body may respond to different types of exercise, how well you might maintain weight loss over time, whether you’re likely to feel full after eating certain foods or whether you’re likely to see improved body composition when consuming a diet high in protein.
Your results come with a clear and personalised report that includes advice on how to shape your fasting schedule, manage portion sizes, and build meals with the right balance of nutrients for your body. It offers guidance that’s tailored to your DNA, helping you make confident, informed choices for long-term weight management and better overall health.
In summary
Fasting, particularly intermittent styles such as time-restricted eating and the 5: 2 plan, has strong evidence for safe, steady weight loss, better blood sugar and healthier heart numbers. Start slowly, stay hydrated and build nutrient-rich meals to maximise benefits while minimising discomfort. MyHealthChecked's Weight Management DNA Test adds a further layer of personalisation, showing which fasting pattern - and which food choices - match your genetic makeup. With the right approach for your body, fasting can become a simple, long-term way to manage your weight and feel your best each day.
References
1. Diabetes UK. Intermittent fasting diets for type 2 diabetes remission. 2024. Available from: https://www.diabetes.org.uk/about-diabetes/type-2-diabetes/remission/intermittent-fasting-for-remission
2. British Dietetic Association. The influence of time-restricted eating on weight management and metabolic health. 2021. Available from: https://www.bda.uk.com/resource/the-influence-of-time-restricted-eating-on-weight-management-and-metabolic-health.html
3. GPnotebook. Intermittent fasting (IMF). 2025. Available from: https://gpnotebook.com/pages/nutrition/intermittent-fasting-imf
4. British Dietetic Association. Ramadan and diet. 2022. Available from: https://www.bda.uk.com/resource/ramadan-and-diet.html
5. Walsh NP, et al. Intermittent fasting: eating by the clock for health and exercise performance. BMJ Open Sport Exerc Med. 2022;8(1):e001206. 2022. Available from: https://bmjopensem.bmj.com/content/8/1/e001206
6. Johnston JD, et al. The role of intermittent fasting and meal timing in weight management and metabolic health. Proc Nutr Soc. 2019;79:76-87. 2019. Available from: https://www.cambridge.org/core/services/aop-cambridge-core/content/view/D1317A634DBD94CC4019E26E435032F5/S0029665119000636a.pdf
7. Harris L, et al. Intermittent fasting strategies and their effects on body weight and other cardiometabolic risk factors: systematic review and network meta-analysis of randomised clinical trials. BMJ. 2025;389:e082007. 2025. Available from: https://www.bmj.com/content/389/bmj-2024-082007
8. Fallaize R, et al. Personalised nutrition and health. BMJ. 2018;361:k2173. 2018. Available from: https://www.bmj.com/content/361/bmj.k2173