Katrina Rendall asks people who cook and eat for a living how they've made the 5:2 diet work for them.

The story of 5:2

We've long been bombarded by too-good-to-be-true sounding fad diet claims. Truth is, two fifths of dieters quit within the first week and just one fifth manage a month on their new diet. So why is the 5:2 (or fast) diet different?

Medical journalist Dr Michael Mosely highlighted the health benefits of intermittent fasting in a BBC documentary in August 2012. His subsequent book, The Fast Diet, which he co-wrote with journalist Mimi Spencer, has sold over 340,000 copies and fans of the diet are said to include Hugh Fearnley-Whittingstall and Beyoncé.

How does it work?

Limit your daily intake to 500 calories (for women; 600 for men) for just two days a week, then eat and drink as normal for the other five days. Experts say you'll lose around 1lb per week.

Karen Burns-Booth, 55, is a food writer and blogger at lavenderandlovage.com...

...She liked the idea of how easily the diet seemed to fit into her lifestyle, which involves a lot of cooking and eating out, and was also interested in the health benefits as she was suffering from insomnia and joint pain. Karen has lost 2 stone 2lb on the 5:2 diet since August 2012 and is still losing 1-1.5lb per week. She says it's by far the best diet she's ever tried.

Karen's top tips

· Hot food keeps me fuller when the weather is cold.
· I try to eat three meals a day and have my main meal in the evening, to prevent hunger pangs.
· I take a homemade lunch to work on my fast days, as most pre-prepared foods are too high in calories

Karen's fast day menu

· Breakfast: A small boiled egg
· Lunch: Curried carrot soup or roast tomato and garlic soup
· Dinner: Tiger prawn curry, made with 125g prawns per person, tinned tomatoes and low-fat yogurt, served with 60g of steamed rice.
· Snacks: A low-calorie jelly or a milky coffee in the evening as a hunger suppressant.

Elly Curshen, 33, is the owner of the Pear Café in Bristol...

...She's never dieted before but wanted to lost a few pounds and was tempted to try the 5:2 after seeing how successful friends had been. Elly lost 1 stone and 5lb on the 5:2 diet since April 2013. She said the hardest bit was getting through a hangover on a fast day.

Elly's top tips

· Use digital scales and weigh everything accurately, then use myfitnesspal.com to calculate calories.
· I save 400 calories for the evening and split them into one big meal plus snacks or two smaller meals.
· Social media is a great source of inspiration - I post pictures of my 5:2 dishes on instagram.com/ellypear and tag them #fastdayideas.

Elly's fast day food

· Breakfast: Plenty of water and a mug of builder's tea with carefully measured milk.
· Lunch: Salad with loads of ingredients in small amounts - lettuce, cucumber, carrot, red onion, pickled beetroot, alfalfa sprouts and a small pinch of my homemade coleslaw (made with yogurt).
· Dinner: Chargrilled vegetables with Puy lentils, capers, poached eggs and courgette 'spaghetti'.
· Snacks: I make crudités while dinner is cooking.

Find more great 5:2 tips and read the full feature in the February issue of Sainsbury's magazine, on sale now.