Weight

Why is it so easy to put on weight and the hardest thing in the world to lose it? I am on a new mission to drop 20 pounds in the next few months. It is going to take some hardcore work, but it is totally do able. I plan on walking in the morning & working out in the afternoon, I have the time why not do it? Now, can I give up sweets? I doubt it but it is worth the try.