As in other novels and short stories by Desai, the focus of Fasting, Feasting is on family relationships and how these determine the fate of the characters, particularly the female ones. The title also calls attention to the rituals of food and eating habits which the novel links to the main theme of family relationships. Food becomes almost an obsession for the characters in the book and their attitudes to it almost come to define them. For example, we can link the word "Fasting" in the title to the character of Uma, as she is left without any intellectual or educational nurture by the conservative values of her parents and, at forty-three years of age, still finds herself living with them and without a life of her own. The word "Feasting", instead, has been applied to her brother Arun, because he has always had the possibility to get the best opportunities and the second part of the novel describes his life in the U.S., whose society is described by Desai as one of excess.
"Different lives," Desai claims, "are parallel lives". This sentence can guide us through the two parts of Fasting, Feasting as continuous parallels are drawn between Uma's Indian family and the Pattons, the American family where her brother Arun stays at in the U.S. The women in both families, for example, tend to be bossed around by the male characters. Uma's fate, described through the word "fasting" in the title, is mirrored by that of her American counterpart, the Pattons' anorexic daughter, once again with reference to food and eating habits/disorders.