The human body is designed to move, and a moving body is a needy body, siphoning off calories to make sure every cell is doing what it’s supposed to do. But even when we’re not exercising, we’re moving and using energy. That’s why NEAT matters. A body that’s sitting isn’t expending energy, so the signals that normally result in you moving—and which, in turn, burn calories—start to check out, molecularly bored with not being called into duty. Meanwhile, the processes that build up fat get busier. When that happens, it gets harder and harder to get off the chair.Alice Park.