Let us count the reasons we're obsessed with protein. For one, you need enough of this benevolent macronutrient to build and repair muscle. It also plays a role in revving fat-burning metabolism and reducing the hunger pangs that can lead to an attack on the vending machine. Additionally, protein works to slow the release of carbohydrates into your bloodstream, which can prevent the sudden spikes in blood sugar that are thought to encourage fat storage and sagging energy levels.