It’s been around for a few years now, and has a large following; fans of intermittent fasting claim that it helps to regulate hormones and is great for weight loss. It can also be seen as a more achievable method of restricting calories than traditional weight loss plans.
In the UK it gained popularity after it featured in the BBC TV series Horizon in 2012. Scientists claim that fasting decreases the presence of a human growth hormone (IGF-1), reducing the ageing process.
Six years on from the TV show, does intermittent fasting really work?
A typical intermittent fasting plan restricts calories eaten for a few days a week. The most widely known, the 5:2, involves eating significantly fewer calories for 2 days a week, with a normal eating pattern for the other 5. Other fasting plans promote a day on-day off routine, with very low calorie days followed by normal ones. A third type uses time, so the fast can be daily, from 8-20 hours a day. The 16:8 is popular amongst body builders – fasting for 16 hours a day, eating for 8.
On the other side of the fence we have a normal calorie restricted weight loss plan. Eating slightly less than you need (200-1000 calories a day, depending on factors like how much you weighed at the start) hopefully leading to safe sustained weight loss.
It’s important to note that fasting does not mean starvation- eating nothing at all for a day or more. This can be very detrimental to both health and weight loss, causing loss of muscle mass and slowing down the metabolic rate.
So which one wins; does intermittent fasting work?
Intermittent fasting works, but according to the latest science, no more so than a normal calorie controlled plan. A more recent study than the Science Direct report linked above showed that after 1 year, both those on normal calorie restriction and the intermittent fasters achieved similar weight loss.
So the question isn’t really “does intermittent fasting work”? but does it work for you? Some people may prefer the daily challenge of undercutting calories by a few hundred – they prefer regular meals and small changes. Others may find this challenging and will prefer a fasting plan – the effort to lose weight seems concentrated into just a few days a week, instead of all the time. The other days can thus feel more indulgent. One person may feel that skipping a meal gives them higher energy levels, while another may feel starving after just one skipped meal.
Intermittent fasting isn’t recommended for the who are pregnant or have medical conditions like diabetes. It can also be difficult for those who may have suffered (or might be on the verge of) an eating disorder – restriction can backfire and lead to subsequent bingeing. But for most of the population it is safe.
Those who promote fasting point out that humans have evolved to fast, our Neanderthal ancestors going hungry between hunts. It does indeed trigger beneficial hormonal responses, like lower insulin levels and improved cell repair.
They both work; done sensibly – and with the correct type of training – intermittent fasting can lead to sustained weight loss and health benefits. But cutting calories the traditional way, or by using an app or organisation like weight watchers works too. At DDW we have got clients six-packs with the 16:8, but we’ve got it with a normal eating plan too.
So consider which one fits your life the best and will give you the best chance of sticking with it in the long term.