What is The Number One Thing You Can Do to Improve Your Health?

"The number one thing one can do to improve his or her overall health and fitness is to give up grains.

Why?

They are a distinctly Neolithic food that humans have yet to adapt to consuming, they contain anti-nutrients (lectins, gluten, phytates) that are unhealthy and should be avoided, insoluble grain fiber (often touted as necessary for gastrointestinal tract health) is non-essential, there are better sources of vitamins and minerals (see meat, healthy fats and vegetables), and they are carb-dense. 

All-in-all they are completely and utterly pointless in the context of a healthy diet; nothing but a cheap source of calories." - Mark Sisson, blogger, speaker, and author