Correct. It is way harder than you describe though. Our bodies can burn only two types of fuel: sugar and fat. What happens is that if you eat a lot of starches, our bodies become adapted to burning sugar and teaching your body to start to burn fat can take anywhere from 2 weeks to more than 3 months depending on the person and how insulin resistant they have become. It kinda hurts to actually re-adapt your body to burning fat. It isn't hard but you have to keep at it because our entire food system has been modified to push starches (sugar) foods. Asking people to become fat adapted is like asking a crack addict to stop using when all they have is crack in their fridge, their friends and neighbours only have crack in their fridge, the corner stores have crack on the shelves, food stores sell 85% crack on shelves and only put the good stuff on the outside isles and have shit selection of that and so forth.