Gradually the interconnected relationships become clear: Victor is still emotionally a child (despite having the body of a man) due to domination by Dolly, who lost her husband (Pete) some years earlier. Delores is burnt-out and going nowhere, which pushes her into sluttish tendencies (including an earlier liaison with Pete and an attraction to Victor). Callie is equally directionless (like a younger Delores) but has the advantage of motherly advice from Dolly. A further complication is that Victor has a crush on Callie (who already has a boyfriend) but is restrained by his reticence, shyness, emotional immaturity and shame about his weight (as Dolly puts it, he is 'husky' or 'well-built').
It is clear that Victor is both at the centre of this 'community' and a somewhat protoplasmic or unformed personality - other people tend to project their emotions onto him while he seems to have none of his own. However, although he is a man of few words (hardly saying anything at all, unless forced) he does have his own hidden feelings. When Dolly suffers a household accident (and later dies) it seems that this will be the moment when the 'real' Vincent breaks forth. Instead the direct opposite occurs; Vincent hides the news of his mother's death so that things won't change at the diner.
The key to Heavy is that it takes its time over everything - the sketching of the characters, their reactions to individual situations and their past history. Initially this works well but, after a while, the expected release never happens - there are plenty of moments when the characters have the chance to change and grow but don't. Instead they just keep on going with the same old daily routine. While this is in harmony with the personalities of these very ordinary people, the movie never rises enough to give us the extraordinary. That said, the performances are generally quite good (if low-key), especially Vince (as most of his communication is carried out non-verbally). There are also several other interesting aspects, such as the echoes of slimming aids wherever Vincent goes and the visions he has of rescuing/saving Callie.