If we want to understand the accumulation of excess body fat, it's tempting to focus our attention on the location that defines the condition: adipose tissue. Ultimately, the key question we want to answer is the following: why does fat enter adipose tissue faster than it exits? It follows that if we want to understand why obesity occurs, we should seek to understand the dynamics of fat trafficking in adipose tissue, and the factors that influence it. Right? I don't think this is right, and here's a metaphor that explains why. The speed of a car depends primarily on the force that its wheels exert on the asphalt below them. If we want to understand why cars move quickly sometimes, and slowly at other times, we should seek to understand the dynamics of how force is transferred from the wheels to the asphalt, and the factors that influence it, right? As you may have already surmised, that wouldn't be a very effective way of understanding car speed. To understand car sp...