The Health Hub

Lose weight with fasting

Lose body fat and live longer on a regime that only involves dieting two days a week. Physician and journalist Dr Michael Mosley tests the latest trend

Does fasting really work?

The trouble with diets is not just the lack of food. It’s the admin. The discipline. The sheer arithmetic, in many cases. If we could trim that down, perhaps cutting back on the food itself would be more palatable. That’s what I sought to find out when I tested intermittent fasting.

With this diet, instead of stressing about calories every hour of every day, you restrict your intake for two days a week.The idea is that, in the wild, periods of feast and famine are entirely normal. Our ancestors didn’t eat four or five small meals a day. Instead they would kill, gorge and then go for long periods without anything to eat.

A growing body of scientific research suggests that following their lead offers speedy weight loss, along with heart, brain and cancer protection. My plan is what I call the 5:2 or ‘fast’ diet.

I eat normally five days a week; then on two days I eat just 600 calories. That’s a quarter of my normal intake (2,500 is the recommended daily allowance for an adult man), split between breakfast and an evening meal.

I start my day with a couple of scrambled eggs or an omelette with ham (300kcal), then drink loads of water, black or herbal tea and black coffee during the day. Then it’s an evening meal with my family around 7.30pm, eating lots of vegetables and some meat (the other 300). On non-fasting days I forget I’m on a ‘diet’ and eat normally: the occasional pizza, cake or biscuits (although my tastes have shifted to more healthy foods).

The results

Weight Before: 187lb; After: 168lb 
Body Fat Before: 28%; After: 19% 
Blood Glucose Before: 7.3 mmol/l; After: 5.0mmol/l 
LDL cholesterol Before: 5.5 mmol/l; After: 3.6 mmol/l

The results from my initial six-week experiment were, frankly, astonishing. As well as losing more than a stone, there were serious reductions in my body-fat percentage and once-worrying markers of diabetes (blood glucose) and heart disease (LDL cholesterol). Yes, there’s still a degree of admin; a little discipline involved, too. But only twice a week. And I fast for no more than 12-hours at a time.

Since the experiment, I have continued on a ‘maintenance dose’, 6:1 – that’s only one day of reduced calories a week. I feel fantastic. When I have a blow-out I return to 5:2 until the weight drops off. If you’re carrying a little too much timbre and lacking the discipline to diet, give yourself a break and go part-time.

Try it yourself

Strip the fat and cut your risk of heart disease – if you're happy to go hungry. This is what 600kcal a day looks like

200kcal + 400kcal: 2 Weetabix; grilled fish and veg 
450kcal + 150kcal: Steak sandwich; 2 apples
350kcal + 250kcal: 2 chicken breasts; a fruit smoothie

Words: Dr Michael Mosley; Photography: David Abrahams; Men's Health