I would agree with Fonty here.
Metabolism will be lowered during the fast itself, but post-fast metabolism will resume as normal.
Lowered metabolism while fasting is the bodies way of conserving energy and food reserves.
Dr Shelton has this to say on the matter........................
"Metabolism is lowered from one-fourth to two-fifths during the fast. This falls quite rapidly during the first part of the fast until the true physiological minimum for metabolism is reached. From this point on, until the return of hunger, metabolism is maintained at a fairly uniform level. If food is not consumed when hunger returns there follows, soon, a rapid dropping of metabolism to new low, but pathological levels."