What is the 5:2 (and 4:3) diet?

The 5:2 diet is a type of intermittent fasting diet.

Here’s how it works:

  • Eat normally (but sensibly) for 5 days of the week (ideally under 2500 calories).
  • Restrict calorie intake to 500-600 calories on the other 2 days of the week, which can be any days but should be non-consecutive. People often choose Monday and Thursday.

The idea is to create a calorie deficit by severely restricting calories on the 2 days, while still allowing yourself to eat normally on the other days.

Intermittent fasting, has been associated with a plethora of proposed health benefits from weight loss to blood sugar balance, reduced inflammation to improved brain function.

Fast Diet book

Published in The Fast Diet book by Dr Michael Mosley in January 2013, it promotes eating what you want for five days of the week, then dramatically cutting calories for the other two.

This part-time dieting approach focuses more on how you eat (and how much) rather than what you eat.

Some people find this diet more manageable than traditional calorie-restricted diets, but it may not be suitable for everyone, especially those with certain health conditions.

So. Whats a ‘4:3 diet’?

Yes .. you guessed it ..

  • Eat normally (but sensibly) for 4 days of the week (ideally under 2500 calories)
  • Restrict calorie intake to under 1000 calories on the other 3 days of the week, which can be any days but can be non-consecutive. People often choose Monday, Tuesday and Wednesday.

MyHSN thinks this is a better way of doing it.

Do diets like this work?

Mm. It’s not clear whether any diet (including 5:2 and 4:3) have a long-term effect – i.e. lower your weight and keep it down.

The problem with dieting, is that people often return to former habits after achieving some weight loss.

Nonetheless, if you are overweight or obese, it leads to many long-term medical (e.g. high blood pressure and type 2 diabetes), surgical and psychological problems. So it’s better to try.

Yes you can.

Other resources

Top tips to help you lose weight
10 obesity facts
How many calories should I eat a day to lose weight?