Fasting is suddenly fashionable

Fasting is suddenly fashionable, and the ancient Christian tradition of not just abstaining from meat but radically cutting down on food for two days a week (Wednesdays and Fridays) has become the new norm.

It’s the 5:2 diet, of course, but Oliver Burkeman asks how we can apply this ‘fasting and feasting’ philosophy to other areas of life.

It sometimes seems as if every other person you meet is following the Fast Diet, also known as the 5:2 Diet, the eating plan first detailed in a BBC2 documentary last summer and then in a bestselling book, by the journalists Michael Mosley and Mimi Spencer. It entails eating very small amounts of food (600 calories for men, 500 for women) on two non-consecutive days of the week, and consuming whatever you like on the other five. [It involves] the crucial psychological insight that extreme self-denial almost never seems to work.

The grander claims made for the 5:2 approach are debatable at best: it’s far from clear that it will stave off ageing, dementia or death. (The best results so far have been confined to mice.) Even Mosley and Spencer admit there’s nothing magic about the 5:2 ratio, or the specific calorie limit for fast days. But because you’re never more than 24 hours away from eating whatever you want, it’s a way of eating less – and of being mindful about what you eat – that people actually stick to. It doesn’t overtax your willpower; nor does it conjure images of a joyless life spent permanently without burgers. “Conscious self-denial,” Bertrand Russell wrote, “leaves a man self-absorbed and vividly aware of what he has sacrificed.” The Fast Diet has a built-in remedy for that.

Which raises a question: might the 5:2 approach work equally well when it comes to those other bad habits we struggle to change – such as failing to exercise, spending too much time online or constantly worrying or complaining? […]

Why does this approach work when others seem to fail?

The fact that extreme self-denial often doesn’t work, or at least not for long, is one of the oldest truths about human nature: Odysseus, according to the myth, had himself bound to the mast of his ship because he knew he couldn’t resist the sirens by willpower alone. If willpower is a “depletable resource”, as experiments by the psychologist Roy Baumeister and others have suggested, then it’s not hard to see one reason for this: the self-discipline muscle simply becomes exhausted. (In one famous study, students made to resist the temptation of cookies and chocolates had less capacity to persevere at geometry exercises.) […]

There are other reasons a plan such as 5:2 might make habit change easier. It’s simple and therefore easy to remember – but it’s also precise, and therefore easy to follow. (Compare that with the food writerMichael Pollan‘s famous summary of the rules of healthy eating: “Eat food, not too much, mainly plants”. Being simple but not precise, this is hard to implement.) It also introduces a challenging constraint, of the kind of thing likely to provoke creative thinking: if you’re allowed to consume only 500 calories a day, or banned from frittering the evening on the internet, you might come up with some imaginative new recipes, or original new ways to spend your leisure time.

This moderate sort of approach won’t work for everyone, nor for every bad habit: sometimes, going cold turkey is preferable. “I can’t drink a little, child, therefore I never touch it,” Samuel Johnson once explained to the poet Hannah More. “Abstinence is as easy to me as temperance would be difficult.” (That’s the Alcoholics Anonymous philosophy.) But if absolutist bans have never worked for you yet, the 5:2 approach could be worth a try.