You may have heard people say that snacking is bad for you. If you snack between meals, they say, you will put on weight and become unhealthy. But that's not the case - it all depends on what kind of snacks you eat. If you choose wisely, your snack can do more than stop you feeling hungry. Healthy snacks can keep your energy levels up during the day - so you can concentrate at school - and give you all the vitamins and minerals that your body needs. Unhealthy snacks, although they might give you an instant energy boost, don't do you any good. They will slow you down in the long run and will lead to weight gain. So, the key is to be able to tell the difference between healthy snacks and unhealthy ones. As a general rule, avoid snacks that have a lot of simple carbohydrates - these are packed with sugar. These are things like soft drinks and chocolate. Healthy snacks contain complex carbohydrates (starches) like whole-grain breads and cereals. Or you can choose protein-rich snacks such as low-fat yogurt or cottage cheese.