I am always tired and drained and honestly the last thing I thought would help was words on a page, but I am pleasantly surprised! This book covered some stuff that's pretty common sense like sleep hygiene, diet, and exercise but it expanded on the science with a sensible plain language approach that makes it more appealing to read. It also goes into the many factors for what's costing you energy both internally and externally and it's useful because some of these factors might not have eve occurred to you but it's plain as day when it's presented to you.
Beyond introducing the different factors that are positives or negatives for your energy (and breaking down the energy into divisions for physical, mental, emotional, and spiritual) it explains the reasoning behind it very well and gives resources to correct them. The book starts off perfectly by talking about when you have no energy you're dividing by zero. I felt that in my bones! The rest of the book helps you stop dividing by zero and start putting gas in the tank.