I love this Movie... I mean Juliette Lewis, Johnny Depp can you say Fantasy...ok prolly too much info any way so, Wikipedia says...

In the small town of Endora, Iowa, Gilbert Grape (Johnny Depp) is busy caring for his mentally handicapped brother, Arnie (Leonardo DiCaprio). His morbidly obese mother, Bonnie (Darlene Cates) has done little except eat since her husband's death, and longs only to see Arnie live to the age of 18. With Bonnie unable to care for the children by herself, Gilbert has taken responsibility for repairing their old farmhouse and looking after Arnie, who has a habit of climbing the town water tower, while his sisters Amy and Ellen do the chores and the cooking. The relationship between the brothers is of both care and protection, as Gilbert continually enforces the 'nobody touches Arnie' policy. A new "Foodland" supermarket has opened, threatening the small Lamson's Grocery where Gilbert works. In addition, Gilbert is having an affair with a married woman, Betty Carver (Mary Steenburgen).

The family is looking forward to Arnie's 18th birthday. A young woman named Becky (Juliette Lewis) and her grandmother are stuck in town when their car pulling an Airstream trailer breaks down. Gilbert's unusual life circumstances threaten to get in the way of their budding romance. In order to spend time with Becky watching the sunset, Gilbert leaves Arnie alone in the bath. He returns home late and wakes up the following morning to find Arnie still in the bath, shivering in the now cold water; his guilt is compounded by his family's anger. His affair with Mrs. Carver ends when she leaves town in search of a new life following her husband's death — he drowned in the paddling pool after suffering a heart attack. Becky becomes close to both Gilbert and Arnie and as she talks to Gilbert she begins to unlock some buried hopes, dreams and happiness. During one of their talks they are distracted from Arnie who returns to the water tower he is forever trying to climb. Arnie is arrested after being rescued from the top of the tower, causing his mother — who has not left the house in seven years — to become the object of pointing, laughing and gawking from the townspeople as she goes to the police station, forcing Arnie's release.

Soon after, Arnie tries to run away yet again from his bath and in his frustration Gilbert finally snaps and repeatedly slaps Arnie. Guilty and appalled at himself, Gilbert takes his old truck and drives away without another word. Arnie also runs away to Becky's, who takes care of him for the evening before he is picked up by his sisters. After some soul searching and help from Becky, Gilbert returns home during the birthday party to apologize to his family

Following Arnie's 18th birthday party, Bonnie climbs the stairs to her bedroom for the first time since her husband committed suicide. Arnie later tries to wake her but discovers she has died. The children, not willing to let their mother become the joke of the town by having her corpse lifted from the house via a crane and helicopters, empty the family home of all of their possessions and set it on fire. A year later, Gilbert describes what happens to his family after his mother's death, as Gilbert and his brother Arnie wait by the side of the road for Becky.