Spinach

Next time you do the weekly shop, back away from the iceberg lettuce and pick up a bag of spinach instead. Each green leaf is packed full of iron and vitamin C, both of which are essential for collagen production. Collagen is the rubbery protein that gives skin and muscles their elasticity and keeps you toned, youthful and glowing. It's also super-filling and very low in calories, which is always a bonus.