As my colleagues have reported (here and here), when it comes down to it, it’s not the body or the metabolism that are actually creating overweight or obesity – it’s the brain. We all know intuitively that poor decisions are what make you gain weight and better ones are what make you lose it. The problem is that over time, the poor decisions lead to significant changes in how the brain governs – and, amazingly, responds to – the hunger and satiation processes. Years of any kind of behavior pattern lay down neural tracks, and overeating is no exception.
Just 10 extra pounds add 40 pounds of pressure on your knees and other lower body joints. That can wear them out quicker. Extra fat can also cause inflammation -- when chemicals in your body damage your own tissues over time, including your joints. Losing even a little weight can ease these effects. If you keep it off, you’re much less likely to get arthritis later in life.