What is the 5:2 diet?
Eat what you want five days a week, dramatically cut the calories for two. The part-time dieting approach that focuses more on how you eat then what you eat has hit the headlines and taken off in a big way.
The practice of fasting has been around for years, with tests carried out to uncover the potential effects as early as the 1940s. However, the dawn of 2013 ushered in a new spin on a practice that had more commonly been associated with religious rituals or even political protests. The intermittent fast, has been associated with a plethora of proposed benefits from weight loss to blood sugar balance, reduced inflammation and even improved brain function.
Despite these varied benefits, the phenomenon of fasting for weight loss in particular was actually set in motion in 2012, when the BBC broadcast a Horizon episode called 'Eat Fast and Live Longer'. Doctor and journalist Michael Mosley presented the diet du jour as ‘genuinely revolutionary’; and as a result, published The Fast Diet book in January 2013. A month after Mosley’s book was published, former BBC journalist, Kate Harrison released her version titled The 5:2 Diet Book. The recommendations in both books vary slightly, though the general principles of the diet remain the same.
Discover our full range of health benefit guides and read more about popular diets such as the intermittent fasting diet and Fast 800 diet. Also find more information about the health benefits of fasting and check out our collection of delicious 5:2 diet recipes.
The simplicity of the diet, and the fact you can eat pretty much what you like five days a week, are key to its popularity. Dieters are recommended to consume a ‘normal’ number of calories five days a week and then, for two, non-consecutive days, eat just 25% of their usual calorie total – 500 calories for women and 600 for men.
There are no restrictions on the types of food you can eat, however a balanced diet is emphasised and it is suggested that women can expect to lose about 1lb a week on the diet, with men losing about the same if not a little more.
Nutritionist Kerry Torrens says:
The 5:2 and similar intermittent-fasting diets are said to be easier to follow than traditional calorie restriction, and an advantage is that you do not have to exclude any food groups. Fasting is a simple concept which appears to promote weight loss, although the hunger experienced can be a limiting factor for some. Many see the eating regime as less of a 'diet' and more as a way of life that can help them maintain their weight loss in the longer term. All the headlines for the 5:2 diet, and similar intermittent-fasting regimes, claim that calorie restriction may be linked with:
- Improving brain function
- Reducing the risk of heart disease, stroke and cancer
- Improving cholesterol levels and blood-sugar control, and be anti-ageing thanks to its possible effect on lowering levels of the hormone Insulin-like Growth Factor -1 (IGF-1)
More evidence is coming to light regarding the benefits of this type of diet although there is clearly a need for longer term human-based studies.
As with all diets, pregnant and breastfeeding women as well as diabetics on medication, should seek medical advice before embarking on a restricted eating programme. Furthermore, this sort of diet can be unsafe for teenagers and children, who are likely to miss out on crucial nutrients needed for growth and may be at risk of developing unhealthy eating habits.
On fasting days some report feeling low in energy, having poor concentration and experiencing headaches and dizziness. Maintaining your hydration with water and herbal teas is important because dehydration can be a cause of headaches and tiredness. Include vegetables and protein on fasting days with some carbs in order to help manage and control your appetite. If you do choose to follow the diet, make sure that your non-fast days are packed with nutritious options, including fruit, veg, wholegrains and lean protein such as chicken, fish, turkey and dairy foods. Some participants choose to ease into fasting by first starting to extend the time between their evening meal and the first meal the next day – the gap the advocates of this approach suggest is a minimum of 12 hours. Avoid fasting on two consecutive days – instead break your week up, for example, by fasting on Monday and Thursday – this helps prevent tiredness.
When you’re following any low-calorie diet, it’s important to make every calorie work – that means choosing nutrient-dense foods. You are far better opting for lean protein like poultry and vegetables rather than calorie-counted ready meals. The latter may seem like the easiest option, but they are not as satisfying.
Please note, if you are considering attempting any form of diet, please consult your GP first to ensure you can do so without risk to health. You may have read that emerging evidence is suggesting a beneficial role of fasting diets for the control and management of Type 2 diabetes, however, refer to your GP if you have diabetes or have any other long-term health condition.
If you're going to give it a go, make sure you include our 5:2 recipes that are low in calories but high in nutrition.
Weight loss and good health can be achieved by following a healthy, balanced diet. Find your perfect portion size, guideline daily amounts and nutritionally balanced breakfasts, lunches, dinners and snacks:
How to eat a balanced diet
A balanced diet for women
A balanced diet for men
A balanced diet for vegetarians
A balanced diet for vegans
Want facts and information on other diets? Read more about other popular weight loss plans:
This article was last reviewed on 4th January 2022.
Kerry Torrens BSc. (Hons) PgCert MBANT is a Registered Nutritionist 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
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