How to boost your metabolism?

What is metabolism? Why is it faster for some and slower for others? Why should we speed up metabolism and how can we do it?

What is metabolism and how does it work?

Can metabolism be 'fast' or 'slow'? Does a slow metabolism make us gain weight? Can you really "damage" your metabolism by following fad diets?

How and why do muscles grow? How to develop skeletal muscles, what exercises to do, what to eat, when to train, when and for how long to rest…