In terms of nutrition, the only thing you should be bothered about are the 3 main Macronutrients. These are - Protein, Fats and Carbohydrates.

However, do you really know what most of them are and what they do, or are you under the impression to eat as much protein as possible, carbs are bad and fats will kill you?

Protein - Is used by the body to help repair and rebuild damaged muscle tissue (usually from working out). Proteins have 4 calories per gram.

Carbohydrates - Are the bodies primary source of energy. Without carbohydrates the body will resort to taking energy from Fats (not body fat) and if Fats aren't present it will eat into muscle tissue. Carbohydrates have 4 calories per gram.

Fats - Are actually essential, fats help transport nutrients around your body, including protein. They act as insulators and protect our vital organs. Fats have 9 calories per gram.