Exercising in Easy... | flickr | Pascal [Ill-advised | Single-handed weight lifting not recommended]
What is the reason Exercising is Easy and Losing Weight is hard?
It's quite Simple (and obvious).
In order to start - and continue - exercising, you "only" need to "be strong" once a day, possibly a couple of times a week - and for a short period. Maybe 30 minutes, maybe an hour. But that's it.
On the other hand...
In order to start - and continue - losing weight (or eating healthier, or spending less money), you need to "be strong" 24/7/365 - because the temptation of food (and calories, or junk food) is always around you.