Lunchbox

Elizabeth White, 33, a researcher, ate a business lunch of roasted peppers with sun-dried tomatoes, rocket salad and a brown roll for a starter, smoked haddock with poached egg, spinach and new potatoes for a main course, bread and butter pudding for dessert and drank two glasses of dry white wine and a cup of tea.

"My job means that lunch time is either feast or famine," says Elizabeth. "Sometimes I skip lunch completely; on other days I'll go to a restaurant or cafe with work colleagues. I wouldn't normally eat as much as I've done today, but we were celebrating and the fixed-price menu was such a bargain, I couldn't resist having a pudding as well as a starter and main course."

According to Juliette Kellow, state registered dietician and deputy editor of Slimming Magazine, such a meal would give Elizabeth 1,760 calories, of which 13 per cent come from protein, 32 per cent from carbohydrate, 44 per cent from fat - of which 13 per cent is from saturates - and 11 per cent from alcohol.

"On first impressions, it looks as though Elizabeth has opted for the healthier options; this meal is absolutely packed with vitamins, minerals and fibre," says Juliette. "However, each course had high-fat extras, such as oily salad dressings or sauces, and this meant the overall fat content was quite high.

"Surprisingly, the sun-dried tomatoes made the greatest contribution to fat intake, being marinated in oil. The bread-and-butter pudding also provided a lot of fat, as did the pepper, which was covered in oil, and the oily dressing poured over the salad.

"As well as being high in fat, this meal contained a lot of calories. Most women with a moderately active lifestyle need around 2,000 calories a day to keep their weight steady; men need around 2,500.

"In the long term, if we regularly have more energy from food and drink than we use up, the excess is stored in our bodies as fat and we gain weight. On the other hand, if we have less energy than we need, we use up our fat stores and as a result we lose weight. Fat provides almost double the calories of protein and carbohydrate, so the easiest way to lose weight, if necessary, is to cut down on the amount of fatty foods we eat.

"A big meal with three courses is likely to provide plenty of vitamins and minerals. Nevertheless, it's easy enough to get all the nutrients you need for good health by spreading your food intake out throughout the day. It's also worth pointing out that although fixed-priced menus in restaurants may leave you with a few extra pounds in your pocket, they may also leave you with extra pounds around your waistline."