The Science: The process of breaking down stored body fat for energy is called lipolysis. The first step of this process is hydrolysis, which chemically requires water molecules to split the fat cells. Furthermore, ATP (the energy currency of your cells) cannot be manufactured efficiently in a dehydrated state. A mere 2% drop in hydration can lead to a 10% drop in physical and cognitive performance.

The Analogy: Water is the oil in your car’s engine. You can have a full tank of premium gas (food), but if the engine has no oil, the pistons grind, overheat, and seize up. You cannot burn fat or build muscle in a dehydrated body.