I've heard that the HCG diet starts with something called "loading days." What is that?

The emphasis here is on consuming foods high in FAT. You may eat whatever you want, but fats are what you need to focus on these loading days. Loading days are to help your body set up the new hCG in your system to start burning fat. You will want to eat or 'load up' on as many fatty foods as you can possibly stand. Dr. Simeons' Protocol states to 'eat to capacity' for those first 2 days on the hCG. The consequence if you don't has been for many to discover that their hunger is still there and can become uncomfortable. If you 'load' properly, you will find that the hCG begins right away to scavenge needed calories from your abnormal fat stores (the really annoying ones like in the gut) so that you feel no real hunger at all.

You DO need to take the hCG on loading days. The loading works with the hCG to prep your bod for the changes coming. There are two primary reasons for loading:1. The hCG effect of burning your abnormal fat stores for fuel does not kick in until the third dose, so eating 500 calories without this effect of hCG will cause you problems in terms of losing structural fat and being extremely hungry until it does kick in. 2. You need to replenish the structural fat stores that are usually depleted in dieting, assuming that you have dieted without hCG in the past.