The 2-Day Diet looks at The Fast Diet and 5:2 Dieting

2 Day Dieting is the new way to lose weight. Ask any group of people and you’ll find that at least a few of them are trying the two-day approach. But with several different diets on offer, how do you choose the one that works for you? Here is our potted guide to the three main diets on offer.

The Fast Diet written by medical journalist Dr Michael Mosley and food/fashion writer Mimi Spencer offers you the chance to ‘lose weight, stay healthy, live longer’. The diet advocates intermittent fasting by slashing your daily calories to 500 (for women) or 600 (for men) for two separate days each week (or three if you want faster results). They broadly advocate eating low GI foods and protein on your ‘fast’ days – the book provides 10 days of dinner recipes – but the rest of the time you eat what you like.

What’s the science? Dr Mosley gives a quick run through of calorie restriction studies on animals and other studies showing the potential health benefits of fasting, the research by 2-Day Diet authors Michelle Harvie and Tony Howell and his own experience of the fast diet, along with anecdotes from others who have tried the diet. The diet itself hasn’t undergone clinical trials.

The 5:2 Diet is novelist and author Kate Harrison’s personal account of her own weight loss journey after following her version of the fast diet which was inspired by Michael Mosley’s Horizon programme. Billed as ‘feast for 5 days and fast for just 2 to lose weight, boost your brain and transform your health’ her diet advocates cutting calories to 25% of your daily intake for two (or more) non- consecutive days of the week. The rest of the week you eat what you like. She suggests eating vegetables, meat, fish and eggs, or ready meals, on fast days and recommends taking nutritional supplements.

What’s the science? Kate explores the potential health benefits of fasting with a short round up of some of the research. She also recounts the experiences of the Facebook group of 50 people she set up to explore individuals’ experiences of the diet.

The 2-Day Diet – written by award winning research dietician Dr Michelle Harvie and Professor of Oncology Tony Howell, the intermittent diet involves two consecutive days of low carb, high protein eating and healthy Mediterranean style eating for the rest of the week. There is no calorie counting (although you eat around ½ your normal intake) and the diet is designed to maximize fat loss, minimize muscle less and keep you feeling full. It’s nutritionally balanced so you don’t need supplements. The authors advise two consecutive diet days because their research showed dieters found it easier, and provide meal plans, recipes and advice on what to eat on diet and non-diet days.

What’s the science? The 2-Day Diet was developed over seven years of research by Dr Harvie and Professor Howell and has been extensively tested on large numbers of dieters. Their results, which they cover in the book, show that intermittent dieting is more effective and easier to follow than a standard, continuous diet – a 65% success rate versus only 40% with a standard diet – and that the 2-Day Diet is also better at reducing levels of insulin (linked to the risk of type 2 diabetes, breast cancer and other diseases). Their research also found that the 2-Day Diet retrained people’s appetites on the five unrestricted days to eat fewer calories.

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