The next time you go shopping, read labels to make important discoveries about all the additives that are in your favorite pre-packaged foods. Chemicals in your food can lead to side effects like feeling tired, bloated or achy. Aspartame is a sweetener in many diet foods that can cause headaches. Msg (monosodium glutamate) lead to headaches and asthma attacks. Phosphoric acid can cause brittle bone disease. Allergic reactions can also be triggered from preservatives, food dyes and flavor enhancers.