Your Body: The Missing Manual

Chapter 2. Fat

It can strike fear in the heart of the most level-headed, body-positive person. Wrapping your body just under its outer covering of skin is a gentle, gelatinous blanket of fat. Serving as insulation, cushioning, an energy reserve, and the focus of intense social scrutiny, fat is one body component that the average person spends more effort to remove than to understand. But fat is no lightweight—although it gets a lot of bad press, it’s as essential to your survival as any of your more popular organs.

Fat is also at the heart of a controversial body mystery. Unlike the fine-tuned processes in the rest of your body, fat storage is the one mechanism that frequently goes completely off the rails. In the process, excessive fat sets up ordinary people for a dismal collection of health troubles.

It’s hard to overstate just how big the problem is. Compared with other animals, obese humans are biological wonders—pound for pound, the fattest creatures on earth. (If you aren’t already feeling self-conscious, consider this: The percentage of body fat of the fattest humans tops that of even the generously proportioned beluga whale.) Still more remarkable is just how common excessive fat is. Despite billions of dollars, high-powered research, and some seriously good intentions, people are getting fatter year after year, in countries across the globe. In the U.S., more than a third of the population is overweight and another third is obese, leaving less than a third of the population ...