The ultimate guide to literally keeping it hot this winter

Though the human body tops out at a steamy 98.6 degrees, it certainly doesn't feel that way on a cold day.   
The science behind staying warm is actually pretty simple: When your body converts calories into energy it produces heat. The more energy you create, the more heat you’ll produce. Keeping that heat close to your body helps you to retain it longer, while feeding your body properly is essential to fueling the fire (so to speak.)  
Once the temperature drops, the most i