What Is 5:2 Fasting? Find Out if It’s Right for You

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If you’re experienced at intermittent fasting, or if you’re still in the research phase, you might be wondering which eating protocol will be the best fit for your lifestyle. Maybe you’ve heard of the 5:2 plan, but you’re not quite sure how it works.

The 5:2 plan is a style of intermittent fasting in which you eat as you typically would five days a week and fast the other two. The 5:2 plan has been around for centuries, but it captured the public imagination in 2012 and 2013 when Dr. Michael Mosley, and his book The Fast Diet, became popular. The Fast Diet promoted a 5:2 fasting schedule for weight loss. 

Since then, celebrities, like Jimmy Kimmel, endorsed the 5:2 protocol and it’s  now one of the most popular forms of intermittent fasting.

How It Works 

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The “5:2” protocol is sometimes called a diet, 5:2 fasting isn’t a diet but an eating pattern. It doesn’t restrict what or how much you can eat (although if you’re fasting for weight loss, you may want to pay more attention to what you eat on non-fast days).

Intermittent fasting is popular because it allows you to eat foods you love and it doesn’t restrict any food groups, which helps you eat a wider range of nutrients. There are no “good” or “bad” foods and fasting days are flexible, allowing you to easily fit an intermittent fasting protocol into your lifestyle.

Like all types of intermittent fasting, the 5:2 plan is very simple. You’ll eat what you like for five days, and practice a modified fast the other two. A modified fast means you’ll reduce your calorie intake to 600 if you’re male, and 500 if you’re female on your fasting days. You might find this calorie-restricted style of fasting twice a week is an easier plan to follow than a schedule like the 16:8, which requires you restrict your eating window daily.

Nutrition on Fasting Day: Common Questions

Are you wondering what and how much you can eat on fasting days with the 5:2 plan? If so, you’re not alone. You’ll also want to know when to schedule your fast, and the health benefits of fasting two times per week. 

What can I eat on fasting days?

You can eat your 500-600 calories however you like, but it’s essential that you keep track and stop eating once you meet your calorie limit for the day. You can eat whatever you like to reach your calorie goal. But beneficial, nutrient-dense foods like leafy greens, berries, whole grains, and protein, are best for optimal health. 

You’ll feel and function at your best when you eat whole foods that are high in nutritional value. Over-processed foods such as crackers, chips, pasta, white rice, or sweets are high in refined carbohydrates, salt, and unhealthy fats which can intensify your hunger and lead to cravings.  Focus on foods that are high in protein and fiber. Both will help you to feel full longer and reduce your hunger pangs.  

You may find soups and broths help you feel more satiated on your fasting days. Broth-based soups are very hydrating and usually contain vegetables and protein, which keep you satiated and provide important nutrients. Some soups you may want to try on fasting days might include vegetable and barley soup with chicken, pumpkin and turkey chili, or beef and root vegetable stew.

Should you stagger your fast days?

While you can fast two days in a row, we don’t recommend it. It’s crucial to nourish your body with healthy foods between fasting days to avoid nutrient deficiencies. To feel your best, try one to three days where you eat as you typically would between your fasting days.

Is fasting twice a week healthy?

Intermittent fasting isn’t recommended for everyone and you should always consult a doctor before you make any significant changes to your diet. If you have a history of disordered eating, are pregnant or breastfeeding, under 18, or have any underlying medical condition such as gout or diabetes, fasting may not be right for you.

Otherwise, intermittent fasting can be a fantastic strategy to help you achieve optimal health. A growing body of scientific evidence suggests that intermittent fasting, in all forms, may havethe following health benefits. 

These include:

5:2 for weight loss

Although fasting twice a week for weight loss may sound extreme to some, research suggests that many people find it easier than traditional calorie-counting diets. 5:2 fasting only requires calorie-counting on two days out of seven, making tracking calories much less difficult. Planning your fast-day meals and snacks ahead of time can make it even easier.

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Studies show that 5:2 fasting and traditional calorie-counting diets achieve the same amount of weight loss. However, if you’re trying the 5:2 plan for weight loss, it’s important not to overcompensate on your non-fast days. 

If you fast two days per week, it cuts out roughly 3,000 calories, which usually translates to about a pound per week lost. But if you overeat on your non-fast days, it can quickly wipe out your calorie deficit and stall, or even reverse, your weight loss.

“Eat what you like” doesn’t mean “eat as much as you want as often as you want.” If you binge on junk food or sweets will sabotage your weight loss goals, whether you’re fasting or not. Common sense and healthy eating strategies still apply. 

Dealing With Hunger and Other Possible Negative Side Effects

You might feel more hungry on the 5:2 plan than with other intermittent fasting protocols. However, your hungry stage should pass quickly. If you drink water and other no-calorie liquids, it can help ease you through your hunger until the feeling passes or it’s time to eat again. But try to avoid drinks with artificial sweeteners and other added chemicals. 

5:2 fasting can also cause:

  • Low energy
  • Feeling cold
  • Poor concentration
  • Headaches
  • Dizziness

The low energy and feeling cold generally improve as your body adjusts to the fasting routine. In the interim, dress more warmly and avoid activities that require a lot of energy if you experience these symptoms. Poor concentration, headaches, and dizziness, on the other hand, are often the result of dehydration, so make sure you’re drinking plenty of liquids during your fast.

How Does the 5:2 Plan Stack Up to Other Types of Intermittent Fasting?

Every fasting protocol has its pros and cons. The 5:2 plan has qualities that make it attractive to some, but problematic to others. Other intermittent fasting protocols such as the 18:6 method might be a better fit, depending on your individual preferences and circumstances.

5:2 fasting requires less effort, since you only think about fasting for two days a week rather than every day. When you eat as you typically would eat five days a week, it allows you to eat socially and less restrictively on non-fasting days. On the other hand, fasting twice a week might seem more difficult for you since the fasting times are longer (making hunger a bigger issue) than with other IF schedules.

Alternatively, a 16:8 style of fasting comes with it’s own positives and negatives. This style of fasting is the same seven days a week. It allows you to eat whatever you want for six consecutive hours a day. You spend the other 16 hours fasting. On this protocol, you spend most of your fasting hours asleep, and your eight hour “eating window” can be whenever you want. 

Since there’s no calorie counting involved, you may prefer the 16:8 protocol. It’s the same schedule every day,  so you don’t have to plan for longer fasts. On the other hand, 16:8 can be a hard pattern to follow if you enjoy eating socially and have people at home who aren’t intermittent fasting.

No matter which eating pattern you choose, intermittent fasting is a flexible, low-effort eating plan that can benefit your health and make weight loss more attainable. The 5:2 eating pattern is one of many intermittent fasting protocols you can try to achieve better health. If this style of fasting sounds like it might be a good fit, give it a try, but always remember to listen to your body and do what’s right for you.

Author's bio

Linda Endicott

Linda Endicott

Linda is an experienced health and wellness writer, a proponent of intermittent fasting. For several years, Linda focused her writer on diabetes and nutrition, and she joined the Simple team to contribute to spreading knowledge about healthy eating habits.