Guidance on training while following this popular diet from sports nutritionist, Emma Barraclough…
Q. A couple of friends are doing the 5:2 diet and I’m tempted to join them. Can I train on my two ‘starvation’ days? Jason White, by email
A. The small number of studies that have looked at the 5:2 diet have so far only used obese, sedentary populations. In those populations, fasting days have been found to help with biomarkers such as insulin sensitivity, which would lower the risk of developing type II diabetes. However, the evidence is much scarcer for healthy, active individuals. The results are likely to be less marked as exercise itself improves markers such as insulin sensitivity.
If you exercise on fasting days you are likely to deplete your glycogen stores significantly. As a result, you would not be able to train at the same intensity as you would be on a non-fasted day, meaning that you’re likely to burn fewer calories per session, and you wouldn’t get the training improvements that you are targeting. This may also compromise your immune function, leaving you more open to developing coughs and colds, and ultimately missing training anyway!
Overall, you are probably better off just training more smartly and eating well.
Expert: Emma Barraclough, SiS sports nutritionist, scienceinsport.com
Image: Anna Lefvert/Shutterstock