The 5:2 diet: what is it and how does it work?

You may have heard of this diet already, but do have a read. I think it is worth trying.


• With the 5:2 diet, you can eat whatever you like five days a week — so-called feeding days. On the two “fasting days” you eat 500 calories if you are a woman, or 600 calories if you are a man.
• It doesn’t matter which days are spent “feeding” and which “fasting”, as long as the fasting days are non-consecutive and you stick to the 5:2 ratio.
• On fasting days you can consume your calories in one go, or spread them through the day — there is no medical research into whether filling up at breakfast or snacking throughout the day is more effective for weight loss.
• A typical fasting-day breakfast of 300 calories might consist of two scrambled eggs with ham (good sources of protein), plenty of water, green tea or black coffee. For a typical 300-calorie lunch or dinner, try grilled fish or meat with vegetables.
• On feeding days you can eat whatever you like. Most dieters, rather than feeling a need to gorge, found that they were happy to consume around 2,000 calories — the recommended daily intake for women (2,600 for men) — and did not crave high-fat foods.
• Contrary to popular opinion, fasting can be a healthy way to lose weight. It can reduce levels of IGF-1 (insulin-like growth factor 1, which leads to accelerated ageing), switches on DNA repair genes and reduces blood pressure, cholesterol and glucose levels.
• According to current medical opinion, the benefits of fasting are unproven. As a diet, it is not recommended for pregnant women or diabetics on medication. Anyone considering a diet that involves fasting is advised to consult their GP first, and to do it under medical supervision. 

• Michael Mosley is a medical doctor, journalist and television presenter. To watch his BBC Two Horizon programme on intermittent fasting, go to the BBC iPlayer (bbc.co.uk/iplayer) or visit tinyurl.com/BBCHorizonFasting