Rishi Sunak Fasts 36 Hours Every Week. Here's Why

UK Prime Minister Rishi Sunak reportedly kicks off his week by observing a 36-hour fast from 5 pm on Sundays to 5 am on Tuesdays, consuming only water, tea or black coffee during that time. He said it was "an important discipline for me" as part of a "balanced lifestyle".

In a conversation with BBC, Mr Sunak revealed, "I tend to try and do some fasting at the beginning of every week as part of a general balanced lifestyle but everyone will do this differently.” Acknowledging a “weakness” for sugary delights, he explained, "It means that I can then indulge myself in all the sugary treats I like for the rest of the week.”

A source close to Rishi Sunak, said, "It's true, he doesn't eat anything at all on a Monday. It's remarkable really, given that he is often on visits or doing PMQ prep on a Monday. It's a real testament to the discipline, focus, and determination that he shows in all aspects of his life and work,” reported the Sunday Times. 

Earlier, the Prime Minister mentioned a preference for Mexican Coke because it is made with "cane sugar rather than high fructose corn syrup." He admitted, "My problem is I love sugary things. I eat a lot of sugary pastries and all the rest of it throughout the week. And I like my food. I don't exercise as much as I used to because of the job. So a little reset at the beginning of the week, a little detox."

Is fasting 36 hours a week beneficial?

While Rishi Sunak's weekly fasting might sound extreme, nutrition expert Adam Collins views it as a stricter version of the popular 5:2 diet, where people limit themselves to 500-600 calories twice a week. “When you add [the two days] together, it's pretty much 36 hours,” he said, as per The Guardian.

However, Professor James Betts from the University of Bath pointed out that a restricted calorie diet, unlike Mr Sunak's 36-hour fasting approach, doesn't put the body into a fasted state. This means the body uses its normal energy stores. He explained that during Mr Sunak's 36-hour fast, the body shifts from using carbohydrates for fuel to using fat. His research found that a more strict fast leads to a greater shift from burning carbs to using fat, though it comes with temporary glucose intolerance.

This kind of fasting could promote "metabolic flexibility," allowing the body to switch between fuel sources. Mr Collins suggested this might lead to "metabolic resilience," helping the body cope with modern diet and lifestyle pressures.

Fasting may also trigger autophagy, a cellular spring cleaning process. However, the claims about fasting's effects, including a longer life, are mostly based on animal research with longer fasts. While fasting might help in weight loss, it could have downsides like muscle loss and reduced physical activity due to lower energy levels, warned Mr Betts.

The cognitive effects of fasting are uncertain. Although burning fat produces ketones linked to mental acuity, the benefits may not be significant after a 36-hour fast.

Mr Sunak's fasting isn't suitable for everyone, cautioned Adam Collins. It is not recommended for those with disordered eating, pregnant women, or those with diabetes. However, the temporary glucose intolerance might benefit people with pre-diabetes by improving insulin sensitivity.