Abstract: An adjustable portion cup includes a bottom and a sidewall defining a scooped perimeter about the upper aperture of the cup. The sidewall is provided with an invertible sidewall panel which defines, in part, the contained volume of the cup in a first position and is operative to reinforce the opposite portion of the sidewall in a second position. The invertible panel is configured so that when displaced from a first position to a second position, it is detached from a lower portion of the sidewall to which it is joined and is in contact with an opposing portion of the cup sidewall, whereby the contained volume of the cup is reduced and the opposing portion of the cup sidewall is reinforced.