The Fast 800

Whatever diet you decide to follow, it is vital that you are getting enough daily protein (at least 50-60g a day), otherwise you will lose muscle.

Based on clinical trials, average weight loss at the end of Week 2 should be around 4kg if you are doing the Very Fast 800, 1.5kg if you are doing 5:2.

But the thing that really sets them apart is that they are a mixture of fats and carbs. And not any old mixture. Broadly speaking, whether it is chocolate or crisps, cake or cheeseburger, they are all made up of roughly 1g fat to 2g carbs. It is a ratio that we seem to find particularly irresistible. The 2:1 ratio Milk chocolate, per 100g – 30g fat

So when she came across Valter’s research showing that short-term fasting could reprogramme a faulty immune system, she decided she would give it a go.

He did these measurements in a lab, but you can get an estimate of yours by putting your resting heart rate into an online calculator, such as fast-exercises.com/fast-exercise-calculator. This calculator will also tell you how you are doing for someone your age. For reasons we don’t fully understand, VO2 max is an incredibly powerful predictor of h

I have a simple regime, which I do most mornings. I get out of bed, put the radio on and do a series of push-ups, squats, abdominal crunches, the bicep curl and the plank – in roughly this order. There are lots of other variants you can try, but these are the basics.

Plenty of black tea, fruit tea, black coffee, water. As for alcohol, an occasional glass of red wine with a meal is okay on non-fast days. If you are doing an 800-calorie day, it’s best to avoid alcohol altogether.

For the Rapid Weight Loss stage of the diet, you eat 800 calories a day. I suggest you stay on this stage for a minimum of two weeks, but you can stay on it for anything up to 12 weeks, depending on your circumstances and how much weight you have to lose.

Cut right back on sugary starchy foods, such as cakes, sweets, biscuits, crisps, fruit juices and soft drinks, as these rapidly turn into sugar in your blood, causing sugar spikes, a surge in insulin and weight gain. Aim to have them less than twice a week.