I always notice this change anywhere after day 7. I always wonder how much of it is an emotional charge from sticking to your goal and how much of it is your body's physical sigh of relief from cleansing itself from the impurities. Your mind feels more clear, the begininng grogginess & lack of energy I always feel at the fast start go away & FINALLY~ so do the hunger pangs. Enjoy it while it lasts ~ there are still tough days even once you get to this point ~ a good time to add some extra steps in your walking or a few extra crunches since energy levels are up!
D~xo