Festival periods bring large quantities of rich food into Indian households, and the customs surrounding that food do considerable portion work without any explicit measurement.
Piece size is fixed by the format itself
Most festival sweets are made in small, discrete units: a single ladoo, a diamond of barfi, a couple of bite-sized fried pieces.
Serving is by piece rather than by scoop, so the amount is decided at production rather than at the table where appetite is doing the deciding.
That is a meaningful difference. A dense food served in a fixed unit is self-limiting in a way that the same food served from a bowl is not.
Sweets arrive alongside food, not after it
In much of India sweets appear as part of the meal or with tea, rather than as a final course eaten on top of everything else.
Eaten within a meal, they compete with the other items on the plate for the same appetite instead of adding to a stomach that is already full.
This also explains why the portions look small to a visitor expecting dessert. They are not dessert portions; they are components of a plate.
Distribution moves most of the volume out of the house
Festival sweets are made or bought in large quantity in order to be given away. Boxes go to neighbors, colleagues and relatives.
The quantity that enters a household is therefore much larger than the quantity that stays in it, and the exchange is the point of the volume.
Reciprocity keeps it moving. A box arriving from one house is usually answered by a box going out, so the same sweets circulate rather than accumulating anywhere.
The calendar creates natural boundaries
These foods are tied to specific occasions rather than being available continuously, which limits them by season instead of by decision.
Many festival cycles also include fasting or restricted-eating days adjacent to feasting days, so the intensity is bounded on both sides by the calendar.
Seasonality reinforces that. Several festival sweets depend on ingredients tied to a particular harvest, and they simply were not made outside their window before year-round supply existed.
The pattern weakens when the format is transplanted
Buying sweets year-round from a shop removes the calendar boundary, and eating them from a large box removes the piece-size boundary.
The foods themselves are unchanged, but the structures that regulated them are absent, which is worth noticing before treating either the tradition or the food as the variable.
Households that keep the format tend to keep the effect. Buying a small assortment for a specific occasion reproduces most of what the calendar and the piece size were doing.