I enjoy studying nutrition and healthy eating and I have been studying it for 10 years. Although I understood it, I still had a weight problem because eating healthy and losing weight do not go hand-in-hand. Eating healthy means putting the right foods into your body. Controlling weight has to do with how MUCH you put into your body.
I had 3 problems in controlling weight. First, counting calories is nearly an impossible task. I did not want to calculate the calories in a dish that I made (adding up how much of each ingredient I used while keeping a running total), write it down, file it, and re-calculate it every time I wanted to eat it, based on the portion size that I ate. Even if I did do all of this, what would happen if, for example, my favorite brand of whole wheat pasta was no longer available, and I had to switch brands? I would have to go back and re-calculate every dish that uses it! It was too much!