How to eat out in London on under 500 calories

For those on a restrictive diet, dining out is your enemy. Worse, it’s a seductive enemy with many guises: from the obvious branding of the Golden Arches to the sinful dumplings of Flesh & Buns or the saucy stacks at Honest Burger. In fact, none of the restaurants on your bucket list will do: after all, no one wants to go out for a “healthy” meal, it’s a regime imposed largely by guilt and a too-tight waistband.

Seemingly, then, the only solution is to remain indoors, joylessly sifting seeds onto the scales to ensure you don’t tip over into gluttony. For those on the 5:2 — last year’s runaway diet — gluttony means eating anything more than 500 or 600 calories (for women and men respectively) on a fast day.

But fear not — restaurants are developing 5:2 menus that allow Londoners to leave the safety of their ascetic kitchens and remain on the straight and narrow.

Feng Sushi will deliver a 5:2 menu to your home or office, offering two deliveries a day, one for breakfast and one for lunch. Brekkie is miso soup both days; lunch options include salmon tataki or detox broth; for dinner there’s a spicy cuttlefish soup on shirataki noodles or broth again. It’s proving very popular in the City; the other day Feng Sushi sent meals to David Baddiel.

“We’re keen on launching healthy eating without dictating to anyone our idea of the ‘perfect diet’,” explains Silla Bjerrum, managing director at Feng Sushi. “But we realised a lot of people are doing the 5:2. Obviously it’s proved very popular because you get days off and you can enjoy a lot of your favourite foods most of the time.”

Admittedly, those who have been on the receiving end of the exhausted despair of a colleague on the 5:2 are right to be sceptical, but Bjerrum is convinced. “I do it myself sometimes. It is tough, but with the Feng Sushi menu you get a considerable quantity of food. This isn’t just eating a bag of carrots and apples on fast days. There’s a psychological advantage to having a meal.”

Sam’s Brasserie agrees: the Chiswick restaurant has also launched a 5:2 menu. Devised by owner Sam Harrison, dishes include watermelon and feta salad (99 calories), pork meatballs (264 calories) and Thai-style fish kebabs (230 calories). The most calorific thing on the sample menu is butternut squash and ricotta frittata with watercress and a mixed seed salad — hitting a whopping 298 calories. You can even have dessert — a passion fruit and mango panna cotta comes in at 144 calories.

But does it taste like food? I tried the watermelon and feta starter, with mushroom and onion stroganoff on puy lentils (194 calories — I’m told you start to talk this way on the 5:2 diet) for my main. While there’s no disguising that watermelon is anything except water it was certainly refreshing, and the stroganoff was creamy and the lentils filling. A trompe l’oeil bowl makes the dish look bigger. All in all, surprisingly satisfying and definitely tasty.

Harrison tells me the idea was to stop dieting excluding you from eating out with friends: “This way you can still have a meal out, even if you’re on a fast day. You can mix and match and still stay under the 500 or 600 calorie mark.” The options are varied; the stereotype of “rabbit food” doesn’t apply here.

Others who have gone 5:2 friendly include Pizza Express — whose Leggera menu offers a number of low-calorie and gluten-free meals — and M&S, which offers ready meals that comply with the restrictive rules of the diet. The perk of the Pizza Express menu is that sinful treats get a low-cal upgrade — the Leggera American Hot is only 396 calories — far more appealing than using your calories allowance on joyless greens.

The superfood salad is only 295 calories and contains four of your five a day. That’s smart calorie maths.

So ditch the scales and toss the seeds — you could dine out and still lose weight on this one for ever.