The growing man might baulk at the shrinking size of recommended portions these days, but how about facing a plate that was entirely bare? The diet world is always coming up with the next fad to shift books and supplements, but the latest – fasting – does seem to have some substance, in science if not at meal times. There’s the popular 5-2 plan, for example – in which, for two days a week, a man might restrict his calorific intake to around just 500 calories – which doesn’t necessarily make for a tiny meal on fasting days, but which certainly requires planning.
Another of the big fasting ideas is time-restricted or intermittent fasting – there are many variants, but the gist could be that for five days a week you eat nothing between the hours of, say, 10pm at night and 2pm the following afternoon; during that time you might well consume as many calories as is healthy for an average man – around 2500; but in the off hours – which, practically speaking, comprises the morning and early afternoon – you consume none at all, excepting water of course. On the two days off – the weekend perhaps – you eat your normal calories as and when you please.
Recent research on animals revealed that intermittent fasting can, in fact, reduce the risk of obesity and related diseases, including liver disease and cancer. Research back in the 1980s suggested that the lifespan of rats is greatly increased when they’re made to fast every other day. Fasting has recently also been found to do the same for mice, relative to mice who had constant access to food – as most of us do.
That’s all great for rodents. But studies are now suggesting that it works for people too – intriguingly, one suggest that such forms of calorie restriction helped the participants lose abdominal fat while preserving lean muscle and metabolism, which are usually sacrificed on a generally low calorie diet. As for longevity? Well, that seems likely too if you’re going to freer of diseases that tend to kill you. Similarly, a study of the 5:2 diet has found that even if you put two groups on the same calories overall, but make one follow the fasting for two days a week, while both groups lose the same amount of weight, members of the fasting group regulate their glucose better – which is good for fending of diabetes – and tend to lose the weight around their middle.
The science is still out on how all this works – just what is the mechanism that allows fasting to have benefits that non-fasting doesn’t, even when the same number of calories are consumed overall? There’s even a suggestion that radiation therapy for those with cancer may be more effective while they’re in a fasting state. There are plenty of theories of course – that fasting is what our ancient ancestors had to do until food had been foraged or caught; you ate when you could but that, inevitably, there were long periods of not eating at all. Or that during fasting you stop using glucose as fuel and start using ketones, which helps burn fat; and that elevates ketone levels – which is key to the body’s regeneration. Fasting seems to encourage cellular regeneration.
And then there is the question of whether you need to fast at all. For the moment doctors are saying it’s worth trying if you’re overweight and want to shift some of the paunch. But if you’re the right, healthy weight, eat well and exercise, then fasting may not be something they’d necessarily recommend. You can just keep doing what you do. Certainly, if you try it, don’t push yourself too hard. Getting by without eating until lunchtime most of the week may not be too much of a stretch, but getting through an entire day with minimal intake can leave you feeling depleted, light-headed and short-tempered. These are not days for heavy exercise, for example, or for a tricky conversation with your partner. Consider what type of fasting best works for your lifestyle, and for your body. And, maybe, for those around you as well…