Of course one isn't going to loose wwight if eat by Fed guidelines! Been there, tried that and Drucker is absolutely correct: only lost a little bit of weight.
It was only when I cut out HFCS and fast food and ate natural foods, cooked at home with no seed oils did I actually lose weight and keep it off.
Once in a while I "cheat", and I can totally feel it without fancy tech, and the length of time between "cheating" episodes keeps getting longer and longer.
(Except the fish & chips at the local Irish pub - but totally worth it!)