The 5:2 Diet | Is It Worthwhile?

The 5:2 Diet

The 5:2 diets involves a person eating 25% of their TDEE (Total Daily Energy Expenditure) for 2 days of the week and then eating normally for the other five days of the week. Overall this results in a reduction of total calories over the weeks. During the ‘fasting’ days, participants are advised to make smarter choices with their meals to make it easier on themselves. This includes drinking lots of water, reducing portions, increasing vegetables and reducing the amount of carbohydrates and fats that you are consuming. The rest of the week you are allowed to eat normally. When you decide to do these two days during the week is completely down to the individual but most people who have done it say that it is easier to spread it out across the week. Those that are pregnant, breastfeeding, diabetic, under 18 or have a history of eating disorders are advised not to do this diet as it can put a lot of strain on your body.


For the 5 ‘non-fasting’ days you can essentially eat what you like. However ‘eat what you want’ isn’t the same as ‘eat as much as you can fit in’. Fasting for two days of the week will cut the calories that you are eating by around 3000-3500 a week (around 1 pound of fat). If you are eating to compensate the calories you missed out on then you will be cancelling it all out. Most find that this doesn’t happen and on the non-fasting days, you are more mindful of what you are eating and have learned how much we need to satisfy our cravings.


Many of us find that exercising whilst fasting has no negative effects. However, the more vigorous exercise should be advised for your non-fasting days when you have more energy. If a person is feeling too weak or tired then exercise should be left until you are feeling better to avoid injury. If you burn 500 calories at the gym then this doesn’t mean that you have an extra 500 calories to eat for the rest of the day.

Spring Vegetable Salad With Maqui Berry Dressing (1)

Research in Health benefits of intermittent fasting:


Intermittent fasting is essentially eating an amount of food in a restricted amount of time. There are studies that are focused around is which show impressive health benefits (Anson et al, 2003; Horne BD, 2011). One of the main benefits is that it seems to be easier for some people than constant caloric restriction (Varady et al 2009; Azevedo et al, 1992). It has also been shown to reduce insulin levels (Anson et al, 2003; Heilbronn et al, 2005; Mattson and Wan, 2005). When comparing those participating in the 4:3 diet (very similar to the 5:2 diet) participants doing the diet lost more weight that the control group (Varady et al,2013). After 12 weeks the fasting group:


 Reduced body weight by more than 5kg
 Reduced body mass by 3.5 kg without altering muscle mass
?  Reduced blood triglycerides by 20%
?  Increased LDL
 Reduced CRP (inflammation marker)
 Decreased leptin by 40%.


Studies in weight loss:


A recent study showed that alternating diet therapy resulted in a 3-8% weight loss over 3-24 weeks. In this exact study the participants found that they lost 4-7% of their waist. When combined with exercise and strength training it is found to be more effective in weight loss (Bhutani et al,2013).

Our articles should be used for informational and educational purposes only and are not intended to be taken as medical advice. If you’re concerned, consult a health professional before taking dietary supplements or introducing any major changes to your diet.

Faye Reid

Faye Reid

Writer and expert

Faye Reid has a Bachelor of Science in Sport and Exercise Physiology and a Master of Science in Exercise Physiology and Sports Nutrition. Faye has worked with numerous high-profile organisations, such as Men's Health, Sky Sports, Huddersfield Giants, Warrington Wolves, British Dressage and GB Rowing, providing her expert sports science support. Find out more about Faye's experience here: She puts her passion into practice as goal attack for her netball team, and in competitive event riding.

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