The mother, who has been morbidly obese since the suicide of her husband, is presented as a fully-developed character, but is also the victim of taunting from both children and adults.
All of the characters felt tangible and real and the intertwined sub-plots were handled expertly. What is not eating him alive is a better question.
His mannerisms and vocal inflection as Arnie were dead on. Nor does the film take them with tragic seriousness; it is a problem, yes, to have a retarded younger brother. The special quality of "What's Eating Gilbert Grape" is not its oddness, however, but its warmth.
But what makes it more than an eccentric coming-of-age movie is that Hallstrom is in the tradition of European directors who have so often brought vitality and freshness to slices of American life. But word of mouth, probably starting with teenage girls but potentially extending to a wide variety of audiences, could reward distrib patience with good long-term results.