Most of us know all about the 5:2 diet. Sometimes recommended by doctors, it simply involves eating normally for five days, then having two fasting days where you consume only 500-600 calories per 24 hours.
The diet on everyone’s lips right now, however, is the 16:8 – a regime which doesn’t involve two days of feeling uber-hungry, but instead, allows you to eat normally between the hours of 10am and 6pm – meaning you have eight hours to consume your daily nutrients (and treats) and a daily 16-hour fast.
Interest has been brewing since a group of 23 obese men and women took part in a study (published in the Nutrition And Healthy Aging journal) and ate abiding by the 16:8 rules – only drinking water after 6pm.
Over a period of three months, the average body fat loss was 3% per person and there was a significant decrease in cholesterol levels, too. Another control group were allowed to eat freely, and the results found those on the 16:8 diet consumed roughly 300 calories less per day, meaning they weren’t bingeing on food during the hours they could enjoy whatever they liked.
So, the advantages of a diet like this include not having to give up any particular foods, and that your body knows what to expect each and every day, hopefully avoiding any of the bloating symptoms sometimes caused by the 5:2. However, if your vice is a glass of wine in the evening, you might find this eating plan tricky.
What are the headlines not telling us?
“Although many of the 16:8 headlines refer to ‘eating what you want’, achieving weight loss on this diet still occurs from a deficit in calorie intake,” says fitness expert Laura Williams (laurawilliamsonline.co.uk). “Rest assured, if you were to really go for it, and have that ability to hoover up thousands of calories in a short space of time, you might not get the results you’d bargained for.”
She also notes the study was pretty small, with 23 completers – who, by the way, had also completed a previous trial, so their awareness around weight loss might be different to participants selected in a randomised controlled trial.
“This method of time-restricted fasting also carries a lower daily calorie reduction (the thing you need to achieve on any diet in order to lose weight) than intermittent fasting,” adds Williams. “You’ll drop around 25-35% of cals on intermittent fasting, vs 20% on time-restricted.”
“Eating this way usually means limiting your intake to three daily meals,” says Rob Hobson, registered nutritionist and Healthspan head of nutrition. “It’s the simplest of fasting methods and once you have the timings right, you can easily fit your meals into the eight-hour window. There’s less time to eat between meals, which is obviously going to benefit your waistline.
“I think this is more realistic than the 5:2 diet,” he continues. “The fact that you can effectively be asleep for most of the fasting time on the 16:8 makes it easier to integrate into daily life.”
Williams can’t decide if she’s a fan, because fundamentally, the diet aims to appeal to the gluttonous, comfort eater in all of us.
“I’ve seen that ‘deprive, deprive, deprive, then… GO FOR IT!’ approach work on first-time intermittent fasters (never seems to work quite as well on return attempts, interestingly),” she continues.
“I’d say it’s worth a go if you don’t have any conditions which may make fasting unsuitable. You’re unlikely to come to any harm going this long without food, as long as you eat well during the time you are eating. I’d suggest chomping as many nutrient-dense calories as you can; think fibre-and-protein-rich minestrone soup, jacket potatoes with tuna, beans on toast – all the stuff that gives you a lot of satiety bang for your calorie buck.”
So, as long as you’re happy to miss out on that evening mealtime experience, the 16:8 diet really could be worth a shot.