Chances are you’ve probably heard of the 5:2 diet, as it has become incredibly popular recently due to the ability to eat normally on 5 days of the week, making it an “easy” diet to follow. However, as always, it is important to remember that everyone is different, so what might suit someone might not necessarily work perfectly for you. Also, as with all diets, it works due to caloric restriction: the consumption of less calories than are expended in a day. A caloric deficit = fat loss!

What is fasting?

Fasting simply means abstention from eating, however there are lots of different types of fasting, including the 5:2 diet.

What is 5:2?

The 5:2 was popularized by British doctor Michael Mosley. It is a popular form of fasting, in which your food intake is limited on the two “fast” days, to around 50% of the Basal Metabolic Rate (BMR). The intake on these days is low enough to still reap the metabolic benefits of fasting (it tends to sit at around 500-600 calories), but are easier to adhere to. It is called the 5:2 because you are “fasting” on 2 out of 7 days of the week. This allows you to eat flexibly on the non-fast days, making it more maintainable, while also allowing for some food to be eaten on the fast days. However, this can be difficult to maintain long term and could still restrict activities on the fast days. 

Why is 5:2 so popular?

A reason why the diet is so popular could be that, unlike low-carb or low- fat diets, no food group is limited or restricted. Instead, the times you can consume any foods is limited, as well as the amount. Apart from this, there are no restrictions, meaning many people  find it easier to adhere to than a calorie-restricted diet.

How can I start a 5:2 diet?

Once you get going, the diet can be very easy to follow, as there are a wide range of calorie-controlled recipes out there for your “fast” days. However, it can take a bit of time to get used to the hunger and the lower-calorie days. It is a very simple concept: you eat normally for five days of the week, and for the other two, you restrict your calorie intake to around a quarter of your daily intake (500 calories for women, 600 for men – however this varies depending on your body composition, activity levels etc so it is advisable to calculate your own daily expenditure). There is total flexibility on when you take these fast days, however you should not take them consecutively. It is common to fast on Mondays and Thursdays, allowing you to eat normally on weekends as well as in between these days.

What do I do on the non-fast days?

While there is no need to calorie restrict on these days, it is important to remember that, if you eat a huge amount of calorie-laden foods such as highly processed foods, you are unlikely to lose any weight following this eating pattern, as your caloric intake will be so high on these days that it will cancel out any benefit from your “fast” days. However, as you are restricting significantly on the “fast” days, you are able to eat normally on your non fast days – meaning no restriction, but eating as you normally would and fuelling yourself with healthy, whole foods. If you are following the 5:2 diet for weight loss, it is important to eat as you would for weight-loss on your non-fast days: eating well and consciously, but not overeating.

What do I eat on the non-fast days? 

There are no specific rules about what you should be eating on the fast days, however most people tend to stick to two larger meals in order to get the most out of the calories for the day. You could prefer a small breakfast to set you up for the day, or skip breakfast and keep to lunch and dinner.  Alternatively, you could eat three much smaller meals. As you are quite calorically restricted on these days, it is advisable to eat mindfully and focus on protein foods, as well as high fibre and volume foods (such as vegetables), in order to fill you up as much as possible. Soups are a great low-calorie option for fasting days, as well as large vegetable-heavy salads. Some meal ideas for fast days could be:

  • Fat-free Greek yoghurt with berries
  • Boiled or scrambled eggs with smoked salmon
  • Grilled fish or chicken with vegetables and cauliflower rice
  • Miso or tomato soup
  • Calorie-free drinks: tea, black coffee and water

There are lots of great resources online with delicious recipes for inspiration on the fasting days!

What are the health benefits of 5:2?

There are many supposed health benefits, however the 5:2 diet has not undergone extensive specific studies to test these hypotheses. Nonetheless, intermittent fasting has been studied, with it showing numerous health benefits. These include:

  • Easier adherence than constant caloric restriction, making it a more long-term weight loss plan.
  • Reduction in insulin levels, as well as improved insulin sensitivity
  • Reduction in the risk of diseases such as diabetes and cardiovascular disease
  • Reduction of ghrelin levels (the hormone that stimulates hunger)
  • Reduced inflammation
  • Live longer: there have been studies to suggest that restricting calories in an intermittent fasting pattern could prolong life.
  • Could reduce cancer risk: there have only been a few studies on this, but the results appear positive.

What about exercise?

It is recommended for optimum results to follow an endurance or strength training program, however people tend to put their rest days on their low-calorie days in order for maximal energy and fuel for the sessions.

Things to remember about the 5:2 diet

  • During the first week of the diet, you are likely to feel quite hungry and weaker due to the calorie restriction. However, you will quickly get used to this eating pattern – just keep yourself busy so you’re not thinking about food the whole time!
  • If you feel faint or unwell on the fasting days, keep snacks with you in case – it is important to prioritise your health and if you feel you could be negatively impacted by this eating pattern, then it might not be for you
  • It is advised to avoid trying the 5:2 diet if you have a history of disordered eating, are sensitive to blood sugar levels dropping, are pregnant, have type 1 diabetes , are underweight, or are trying to conceive.

To sum up

The 5:2 diet can be a great method for some to lose weight and maintain a healthy lifestyle, as it allows you to eat normally on 5 days of the week. As always, healthy and balanced eating is the priority, and it is important to bear in mind that the 5:2 diet will not suit everyone.

Written by Natasha Howe