Right now the whole of London seems to be on the 5:2 diet — eating normally (2,500 calories for men) for five days, then being hungry and irritable (600 calories) on the other two. Personally, I prefer two minutes of metabolism-boosting exercise every morning before breakfast, as outlined in the new book The Fat Burner’s Bible. You do eight bodyweight exercises in 15-second bursts and after six weeks you look buff enough in your Orlebar Brown Bulldog swim shorts (above, £225) to eat and drink with impunity.