Fast and Hard? The 5:2 Diet Phenomenon | Viva! - The Vegan Charity

Fast and Hard? The 5:2 Diet Phenomenon

Fast and Hard? The 5:2 Diet Phenomenon

The world is awash with diets promising they’re the one for you. Juliet Gellatley looks at the science behind ‘intermittent fasting’ and asks does it work, is it healthy and is it safe?

When I first heard about the 5:2 diet I was sceptical but the attitude of friends aroused my curiosity. It’s working for them! Science doesn’t totally support fasting and neither do I. Complete withdrawal of food can have short-term side effects such as headaches, dizziness, fatigue, abnormal heart rhythms and low blood pressure. Longer-term, it can affect the immune system and vital bodily functions, even damaging the liver, kidneys and other organs. But the 5:2 diet is not about total fasting – it allows 500 calories a day for women and 600 for men, two days a week. The other five you are encouraged to eat healthily but your calorie intake isn’t restricted.

V Plan with 5:2

Viva!’s V Plan Diet is vegan and shows how to eat well for life - the best way to lose weight healthily and safely. Think of the 5:2 diet as a tool within it to speed up loss of body fat. The V Plan doesn’t restrict calories and there’s no boring measuring of portions!

Research shows the 5:2 diet works. Dr Michelle Harvie, a dietitian at the Genesis Breast Cancer Prevention Centre in Manchester, has spent years studying how to help women lose pounds because of the link between overweight and breast cancer. Her recent trials involved 115 women – some ate a 1500 calorie Mediterranean diet all the time and were encouraged to avoid alcohol and high-fat foods.

Another group ate normally five days a week but ate 650 calories on the other two. After three months, women on the 5:2 diet lost an average of 4kg (8lb), while those on the full-time diet lost an average of just 2.4kg (5lb). Dr Harvie believes the 5:2 diet is more effective because people stick to it. Having reached their intended weight, they reduce to just one calorie-restricted day a week and that’s enough to stop the weight slipping back.

“It is doable and easier than a normal diet – and that’s the reason it is successful.” If you eat 500 or 600 calories two days a week - and don’t overcompensate by stuffing yourself rotten the rest of the week - you lose weight steadily.

Medical journalist, Dr Michael Mosley, who researched the diet for BBC’s Horizon in 2012, believes excess weight is linked to insulin. When we eat ‘junk’ carbohydrates such as white bread, white rice or pasta, cakes, fizzy drinks and alcohol, our blood glucose levels rise and the hormone insulin is secreted. Insulin regulates this sugar rush, helping our cells to store it as glycogen.

The fat controller Dr Mosley adds: “Insulin is a fat controller, both storing fat and inhibiting its release. Insulin makes you fat! Eating too often and junk carbs can lead to raised insulin levels so that our bodies continually store fat. Just a few hours of fasting turns off the ‘fat storing’ and turns on the ‘fat burning’ mechanisms.”

5:2 fasting also reduces a hormone called IGF-1 (insulin like growth factor 1) which promotes growth and in later life, raised levels are linked to cancer and accelerated ageing. Dr Mosley tried the 5:2 diet for three months and lost 9kg (19lb). Tests on his fat, insulin and IGF1 levels showed his risk of diabetes, heart disease and cancer were significantly lowered.

What of my friends on the vegan version of the 5:2 diet? Lola Grant (46) says: “The hunger comes and goes in waves on fasting days and I feel slightly irritable, especially around people eating! But I feel lighter, more energetic and lost half a stone in just one month. I am not very good at self-denial (she says stuffing a marshmallow in her mouth) and it works for me.” Cathy Keegan (55) enthuses: “I’ve lost almost a stone in seven weeks, I sleep better, have more energy and my stomach is flatter. It’s the only diet I’ve stuck to – ever!”

Available from Viva!

Note: we do not stock the fast diet and the 2 day diet as they allow meat, fish and dairy; the former also refers to animal experiments.

Viva!Health Diet Plan: Includes V Plan Diet (colour guide) and 5:2 Vegan Style (fact sheet with recipes) Online and By mail: send £5 (inc p&p) (payable to Viva! with your name and address) to: Viva!, 8 York Ct, Wilder St, Bristol BS2 8QH. By phone 0117 944 1000 (9-5, Mon-Fri)