Don't work out on an empty stomach. Eating a carbohydrate-rich snack - bagels, muffins, cereals, pasta or potatoes are ideal - two to three hours before you exercise allows time for digestion and tops up your body's stores of glycogen, the fuel for physical activity. Remember that high-calorie or fatty meals take longer to leave the stomach and may predispose you to a stitch or gastro-intestinal discomfort.

Do include some protein-rich foods such as eggs and dairy in your daily diet. A recent study at the University of Illinois found athletes who did so were faster, stronger and leaner. Professor Donald Layman, who headed the study, said there was "an interactive effect" when protein and exercise were combined. Protein foods contain a high level of the amino acid leucine, which stimulates muscle synthesis and recovery.

Don't restrict porridge to breakfast. It is the perfect pre-workout snack, say sport physiologists at Loughborough university. Because it has a low glycaemic index when made with water, porridge provides a longer-lasting energy boost for athletes than a hi-tech isotonic sports drink.

Don't neglect your iron intake. More than a third of UK women don't get their daily iron requirement (14.8mg) from the best food sources such as red meat, chicken and eggs and this makes getting fit harder work. A study in the American Journal of Clinical Nutrition showed that women given a six-week course of iron supplements saw improvements of up to 200% in their fitness and felt less breathless than those who took a placebo.

Do eat unsweetened tinned peaches. Remarkably, a study at Nottingham university in which athletes were given either a high GI breakfast such as white bread with jam or a low GI meal of tinned peaches and muesli and then asked to perform a 60-minute run three hours later found the peaches group performed much better.