Rishi Sunak's friend has revealed the prime minister does not eat on Mondays as part of an intermittent fasting practice.
A source disclosed the 43-year-old will have stopped eating by 5pm on a Sunday and is not allowed to touch food again until 5am on a Tuesday. During this period he allows himself to drink only black coffee and water.
Mr Sunak is said to have followed the habit for years to stay in shape and also to follow principles in line with his Hindu beliefs, with the religion encouraging fasting.
The prime minister is also a famous teetotaler and participates in Peloton classes - admitting that he favours one session that is done to Britney Spears’ hits.
However, the father-of-two is not without his vices. He has previously told bemused students about his "Coke addiction" and Sunday's Times article saw his pal disclose that he relies on the odd pastry to get him through the morning on other days.
The unnamed friend is quoted as saying: "It's remarkable really, given that he is often on visits or doing PMQ prep on a Monday.
"It's a testament to the discipline, focus and determination he shows in all aspects of his life and work.''
Mr Sunak is also known to avoid smoking and has previously driven through efforts to curb vaping products being sold to teens.
In 2022, he told an interviewer: "I do intermittent fasting, so on most days I have nothing for breakfast.
"Otherwise, we have Greek yoghurt and blueberries during the week. And then I have a second breakfast mid-morning, which is a cinnamon bun, a pain au chocolat or a chocolate chip muffin."
But on Sunday the scale of his diet was made public for the first time.
What is intermittent fasting?
The diet strategy has become popularised in recent years.
Not only does it see the participant consume fewer calories but it also allows the body to induce ketosis - a metabolic state which promotes fat loss.
There are different strategies. Some go without food for 16 hours every day but others will not eat for a 36 hour window just once per week - Mr Sunak being one of these.
It is said to extend lifespan, lower the risk of cancer and boost immunity.
Harvard Medical School researchers in 2020 found that it may enhance the body’s defences against oxidative stress and increase disease resistance.
Author Dr Mindy Pelz, author of Fast Like a Girl, has said: “Thirty-six hour fasts are where to start to see fat loss and anti-ageing. This length of fast will force your body to burn stored glucose [so that it] begins to burn fatty acids from stored fat for energy.”