But it is, that's my point. If I went out and jogged instead of being on HN, and cut my portions by 25-30%, I'd be fit as a fiddle. But I simply don't do it because <excuses>. There's nothing complicated about it at all.
This is a problem that so many people are fighting against, and mostly we are losing. Exercise may help, eat less may help, they are not ultimate solutions. The fundamental thing or the root cause is that our metabolism becomes slow which tends to accumulate more fat, and the energy being absorbed from food is not enough per meal, so we tend to eat more. Increasing the quality of food without junk, all organic and fresh, no transgenes, no trans-fat, is the ultimate solution along with regular exercise. But we may not be able to afford or be willing to pay the cost for staying healthy. It has a long term impact.
When you think most problems people deal with are simple and similar. Take your example, overweighted. You think the solution is simple: exercise more, eat less. Usually it's from an engineer's brain. But probably, you forgot to take your excuses into consideration, that's why you over simplified it. Then you struggled with it like many other people. If you do take all of the aspects into consideration, it's no longer simple any more.
When you easily felt bored after you have learn something new, I think it's lacking of depth to learn it more or to find more fundamental problems in it before you skip it.
I agree with you in most of the points, but I wish I could see that you can really dive into something and make it a big different for the world. If you cannot find anything with enough challenge for you, you may want to visit here: http://kck.st/JNqv8z because most people think that they are overwhelmed.