If you want an explaination to give to people and you want it to be simple try:

I know I need to cut down foods to lose weight and be healthy.

My options are low fat and low calorie but I found I was always hungry and still had problems losing.

I discovered that fat doesn't make you fat if you cut out the carbs like sugar, flour and rice. Then I get to eat and get full and burn fat.

So i'm trying that for a while to see how I feel.