pack on the pounds

Verb

 * 1)  To gain weight, especially as a result of vigorous or excessive eating.
 * 2) * 1936, "Today, these healthy Dionne Quins had Quaker Oats" (advertisement), Windsor Daily Star (Canada), 3 Dec., p. 27 (retrieved 13 Nov 2010) :
 * For growing youngsters, this marvelous nourishment helps pack on the pounds, adds inches to height.