LUNCHBOX

Michelle Green, 24, works in advertising Pret a Manger salad club sandwich and a packet of Walkers cheese and onion crisps, with a small bottle of fizzy water and a milky coffee

According to Juliette Kellow, state registered dietician and associate editor of Slimming magazine, such a lunch would give Michelle 550 calories. Broken down, Michelle would be getting 19g of protein, 75g of carbohydrate, 22g of fat of which 5g is saturates, 8.2g of fibre and 1.3g of sodium.

Ms Kellow said: "The total fat content of this meal is pretty good although it still provides slightly more calories from fat that is currently recommended - no more than 33 per cent. But the proportion of calories coming from the different types of fat is well within guidelines."

Fibre content was also good, as was the intake of vitamins and minerals, including iron, calcium and several of the B vitamins. Ms Kellow warned that the salt intake was on the high side, mainly due to the crisps and houmous. Current healthy eating guidelines recommend a reduction in salt from 9g to 6g a day.

Those guidelines recommend that most people should eat five portions of fruit and vegetables a day. Although the sandwich contained a small amount of salad it couldn't be counted as a whole portion so it would be a good idea to add a piece of fruit or a fruit salad. Fat content could also be reduced by picking low-fat crisps.

The verdict? "All in all this is a reasonably nutritious meal and goes to show you can still include treats such as crisps as part of a balanced, varied diet"

Glenda Cooper