Indian food carries a reputation in the United States for being heavy and rich. That impression is accurate about the food most Americans encounter and inaccurate about Indian cooking generally.
The restaurant menu was never a representative sample
Dishes that established Indian food abroad were drawn largely from a celebratory and commercial repertoire, the food cooked for occasions rather than the food cooked on a Tuesday.
Everyday Indian home cooking runs to simply cooked lentils, dry vegetable preparations with modest oil, plain rice and unenriched flatbread. Very little of that appears on an American menu.
The selection was commercial rather than deceptive. Restaurants export the dishes that travel well and justify a restaurant price, which are rarely the plainest ones.
Restaurant technique adds fat deliberately
Fat carries flavor, holds a sauce together and gives a visible gloss, so commercial kitchens use more of it than a household would. This is true of restaurant cooking in every cuisine.
Cream and butter also stabilize a sauce that must be held and reheated across a service, which is a practical requirement rather than a flavor choice.
Portion and course structure change the load
An Indian meal at home spreads several small servings across the plate, and any one rich item is a fraction of the whole.
An American restaurant serves a large bowl of one gravy dish with rice and bread as a complete meal, so the richest element becomes the majority of what is eaten rather than a component.
The accompaniments compound this, since naan is an enriched bread and restaurant rice is often cooked with fat, where the home versions of both are plain.
Buffets change the picture further
Buffet service favors dishes that hold well in a warmer, which means the sauced and fatty preparations rather than the dry, freshly finished ones.
Vegetable dishes that would be cooked to order at home appear stewed and softened, which flattens both texture and the impression of the cuisine's range.
What the home repertoire actually looks like
A typical home meal centers on a legume, a vegetable and a grain, with fat used in measured spoonfuls for tempering rather than poured for richness.
American cooks working from Indian home recipes rather than restaurant ones usually find the results lighter than expected, which is a fair reflection of how most of the food is actually eaten.