We all know that fast food is not usually very healthy. Burgers and chips contain a lot of salt and fat, both of which can lead to health problems when eaten in large amounts. Another problem is calories. Teenagers need more calories than adults because they’re still growing and typically more active, but it’s still important not to overdo it. A typical medium BigMac meal with a coke, for example, is 1000 calories. That’s a big chunk of your recommended allowance with hardly any vitamins or minerals to show for it.