You are what you eat should really be stated ...
Your body is what you feed it.
If you want to maximize your life and perform you need to have a healthy body and supplying it with good food & water is the most important thing to do. If your body performs well you feel better and perform better.
The body can get by on very little. It can even turn shoe leather and cardboard into body products. People can live on meat and potatoes, cooked rice and beans and some appear to function on highly processed and chemical laden fast foods. But this is not the best food. Why not give the body the best. Do you put second had recycled oil in your car? Would you put dirty fuel into the gas tank? NEVER!!!!
Raw Live Fruits, Vegetables, & Nuts are the best things to eat because they supply the best pre-built products for living bodies.
By supplying these pre-built components your body expends less time and energy to fabricate these complex molecules that it needs to repair itself and function.
The absolute best way to ingest nutrition is by juicing. Juice requires almost no processing to assimilate and has most of the nutrition that the plant material contains. Fruit juice is totally digested in 15 minutes and vegetable juice takes 20 minutes.
The idea here is be sure and supply the live food. You don't have to eliminate the junk you have been conned into eating. You just need to have a generous supply of good nutritious food.
Food mixing is very important to proper efficient assimilation. Some combinations severely effect digestion and can be detrimental.
The timing of what you eat is also important to peak performance and maximum efficiency. Fruits and fruit juices are best in the morning. Fruit should always be taken alone or not at all. Try not to eat within 2 hours of sleeping.
Eat right and live well. Feel good and perform.