Lentils

A great source of protein and carbohydrates, lentils are also low in fat and calories, meaning they'll keep you feeling full up and satisfied without adding to your waistline. They are also rich in B vitamins, iron, magnesium, potassium and zinc - all of which your body needs to keep energy levels revved up. Beans, meanwhile, are packed with fibre, which results in a slow release of glucose and sustained energy throughout the day, rather than the short spike in blood sugar that higher GI foods - such as white rice and pasta - can cause.