A Guide To The 5:2 Diet

The 5:2 diet is a popular type of intermittent fasting (IF) method, and is a great introduction to the world of IF. Here's what you need to know.

The 5:2 diet, also known as โ€œThe Fast Dietโ€, involves eating normally for 5 days of the week, and then on then on the other 2 days limit your calories to about 500kcal for women, and 600kcal calories for men.

The 5:2 Diet Explained ๐Ÿ’ก

The 5:2 diet is a weight loss method โ€“ helping you eat in a caloric deficit across 7 days (one week).

  • For 5 days you eat at your maintenance calories
  • For 2 days, you eat a quarter of your typical food intake (about 500-600 calories).

Published in The Fast Diet book by Dr Michael Mosley (a former doctor turned journalist and presenter) who popularised this diet, says it’s not exactly fasting. Instead of not eating at all, you’re just eating less.

On the 2 x low calorie days, you can have your calories in one meal or spread them out during the day.

Amendments to the 5:2 Diet

Dr Mosley later tweaked the 5:2 diet, suggesting 800 calories on fasting days” and following a Mediterranean diet every other day.

This method has been backed up with several studies showing promising weight loss results and remission from type 2 diabetes with the calorie intake at approximately 800 calories on the fasting days. Plus, the Mediterranean diet is perhaps one of the most studied diets, particularly around cardiovascular health.

How to Follow the 5:2 Diet ๐Ÿฝ๏ธ

Following the 5:2 diet is pretty simple. You can eat any type of food, but itโ€™s good to focus on a balanced diet. if you’re following the 5:2 diet, you will want to eat foods like:

  • Lots of plant-based foods like fruits, veggies, whole grains, nuts, and legumes. These are usually fresh, seasonal, and local.
  • Olive oil as the main fat source.
  • Cheese and yogurt in small to moderate amounts every day.
  • Fish and poultry in small to moderate amounts, eaten a few times a week.
  • Red meat only occasionally and in small portions.
  • Fresh fruit for dessert, and sweets with added sugars or honey just a few times a week.
  • Wine in small to moderate amounts, typically enjoyed with meals.

Regular Eating Day Diet Example (2000 calories)


  • Oatmeal (1 cup cooked) with honey and berries
  • Greek yogurt (1 cup)
  • Almonds (handful)

Morning Snack

  • Apple
  • A small handful of walnuts


  • Grilled chicken salad with mixed greens, cherry tomatoes, cucumber, and olive oil dressing
  • Whole grain bread (1 slice)
  • A piece of fruit (e.g., orange)

Afternoon Snack

  • Carrot and cucumber sticks with hummus
  • A small piece of cheese


  • Baked salmon (150g)
  • Quinoa (1 cup cooked)
  • Steamed broccoli and carrots
  • Small glass of red wine (if you want)

Evening Snack

  • Dark chocolate (1 small square)
  • A handful of berries

Low Calorie Eating Day Diet Example (800 calories)


  • Boiled eggs (2)
  • A small orange


  • Salad with mixed greens, cherry tomatoes, cucumber, and a splash of lemon juice
  • Grilled chicken breast (100g)

Afternoon Snack

  • A few slices of cucumber


  • Grilled fish (100g)
  • Steamed spinach and zucchini


  • Herbal tea (unsweetened)

Try not to fast on two days right after each other. Spread it out, like fasting on Monday and Thursday. This can help keep you from feeling too hungry.


Staying hydrated is key. Drink lots of water and herbal teas. This helps avoid headaches and feeling tired. Some people find it easier to start by increasing the time between dinner and breakfast the next day to at least 12 hours.

Your maintenance calories will depend on your age, height, current weight and activity level. Make sure you figure out the right maintenance calories for you before starting this diet to avoid under-eating. You can use this free calorie calculator.

How Quickly Do You Lose Weight on the 5:2 Diet? ๐Ÿค”

This depends how much weight you want/have to lose, and how many calories you’re consuming on your regular eating days.

Women often lose about 0.5k per week, while men commonly lose up to 1kg per week on the 5:2 diet.

Is the 5:2 Diet the Same As Intermittent Fasting? ๐Ÿ”

The 5:2 diet is often considered a form of intermittent fasting, but it’s slightly different from traditional intermittent fasting methods. Here’s how:

  • Intermittent Fasting (IF): Traditional IF involves cycles of eating and fasting periods. The most common forms include daily 16-hour fasts or fasting for 24 hours, twice per week.
  • 5:2 Diet: In the 5:2 diet, you eat normally for five days of the week and then restrict your calorie intake on the other two days. It’s a form of intermittent fasting because it includes regular short-term fasts (the two low-calorie days).

TLDR: While the 5:2 diet is a type of intermittent fasting, it focuses more on calorie restriction during the fasting days rather than complete abstention from food. Also, the fasting days in the 5:2 diet are not consecutive, which differentiates it from some other forms of intermittent fasting.

What makes intermittent fasting / the 5:2 diet popular is they don’t focus on eliminating certain food groups or ingredients. Rather it focuses on the time and duration of a non-eating period.

Tips for Starting Your 5:2 Diet ๐Ÿ’ช๐Ÿป

To help you start your first 5:2 diet and successfully incorporate it into your lifestyle, try these tips:

Before you start:

  • Choose the days you wish to fast
  • Define your health goal and measure to collect a baseline
  • Plan your meals/snacks ahead to ensure they fit into your calorie restriction
  • If you are overwhelmed or concerned about fasting, speak to a health professional or engage a coach to help you navigate the process

During your fast days:

  • Focus on nutrient-dense whole food meals that fit into your calorie
  • Avoid and limit processed or junk foods
  • Keep hydrated by drinking water and herbal tea throughout your fast
  • Exercise before you consume a meal or snack
  • Practice slow and mindful eating when consuming meals
Just because you limit your calorie intake on two days, it doesnโ€™t mean you can eat anything you want and as much as you want on the other five days. It is recommended you are still mindful of your portions and the type of food so you donโ€™t overeat or consume unhealthy foods outside of your fast. After all, itโ€™s not 5 โ€œcheat daysโ€!  

Health Benefits of 5:2 Diet ๐ŸŽ

  • Helps you lose weight.
  • Improves blood sugar levels.
  • Lowers cholesterol, and enhances heart health.
  • Potentially boosts cognitive function.
  • Decreases body inflammation.
  • May extend lifespan.
  • Improves metabolic markers.

Weight Loss

Six out of eight human trials into the effects of modified fasting regimens, such as the 5:2, reported significant weight loss in those who fasted compared to the control group.

In two trials of approximately 100 women, it was the 5:2 intermittent-fasting regimen resulted in the same weight loss over a 6 month period as those participants who reduced their daily calorie intake by 25%.

When compared to the conventional method of daily energy restriction, participants following a 5:2 plan consuming 600-650 calories on fasting days lost twice as much body fat in this 2013 study.

A study into fasting for 5 days consuming 700-100 kcal/day every month for 3 months was also found to reduce overall body weight as well as trunk and total body fat.

Disease Prevention

Intermittent fasting methods that reduce the calorie intake on 1 or more days each week have been found to result in increased levels of ketone bodies on the fasting days. Ketones not only provide fuel, but they also help to regulate the expression and activity of several proteins and molecules that are known to influence our overall health and aging.

Beyond weight loss, many of the studied benefits of intermittent fasting methods including the 5:2 diet reveal improvements in glucose regulation, blood pressure and heart rate. All of these health parameters will influence the occurrence of disease.

Studies also found intermittent fasting with calorie restriction just 1 day a week is an effective solution to lowering cardiovascular disease risk in overweight women.

Promise has been seen for intermittent fasting methods such as the 5:2 and calorie restriction in reducing fasting insulin levels and insulin resistance in people who are overweight or obese helping to reduce the risk of type 2 diabetes.

Itโ€™s important to note, the researchers called for more studies to be undertaken and no suggestion was made that fasting was superior to overall calorie restriction.

Pros of 5:2 Diet โœ…Cons of 5:2 Diet โŒ
๐ŸŸข No foods are restricted or demonised
๐ŸŸข You can decide when to schedule your fasting days in the week
๐ŸŸข Can be easy to schedule around social commitments
๐ŸŸข May experience benefits such as weight loss and blood sugar regulation
๐Ÿ”ด 5:2 doesnโ€™t replace healthy nutritional basics
๐Ÿ”ด Need to plan and weigh out low-calorie meals/snacks on fasting days
๐Ÿ”ด May experience hunger pangs and other side effects
๐Ÿ”ด People can binge or overeat on non-fasting days

Side Effects and Risks of the 5:2 Diet โš ๏ธ

Intermittent fasting can result in some side effects, particularly if you havenโ€™t fasted before. These are usually minor and generally subside quickly once your body is used to fasting. And remember, with the 5:2 plan you are able to eat on your fasting days, just not much.

Some of the most common side effects you may experience on the fasting days include:

  • Hunger
  • Tiredness
  • Headaches
  • Poor or reduced focus
  • Mood swings
  • Irritability
  • Nausea

Is 5:2 Right for You? ๐Ÿ™‹๐Ÿผโ€โ™€๏ธ๐Ÿ™‹๐Ÿพโ€โ™‚๏ธ

Intermittent fasting is not suitable for everybody. This includes the 5:2 diet and even the new modified plan of increasing your calorie intake to 800 cal on the fasting days.

Fasting isn’t recommended for:

  • People who are pregnant, breastfeeding or trying to conceive
  • People under 18 years old
  • People underweight
  • People who have/had an eating disorder
  • People with anemia, hypoglycemia or type 1 diabetes

Always consult a trusted healthcare professional before starting a new diet to make sure it’s safe for you.

The 5:2 diet is a good choice for beginners to intermittent fasting and for those looking to lose weight without sticking to a low-calorie diet every day.

It does need some planning, especially for what to eat on fasting days. At first, your body might need time to adjust, and you may feel hungry or a bit lightheaded during the first few weeks.

Before starting any fasting diet, especially if you have health concerns or specific dietary needs, it’s important to talk to a healthcare professional.

Explore in More Detail ๐Ÿ•ต๐Ÿป


Leave a comment