it's meant to give you that extra boost, but if normal food optimising is working for you then it doesn't matter.
Dependingon how much you weigh you are given so many units to use per day, in my case 19 units, there is a column for 1 unit, 2 unit and 5 units and 8 unit, so I had 2 x 5, 1 x 1 unit and 1 x 8 unit. You have to stick to it. I thought I read somewhere on here someone had lost 6 lbs in one week, I am close to my target weight so I didn't think I would lose much so was very happy when I did. Anyway, this week don't seem to be having much luck.