Indian regional cooking uses markedly different fats, and the choices are not interchangeable. Each behaves differently under heat and contributes differently to the dish that results.
What smoke point actually measures
Smoke point is the temperature at which a fat begins to break down visibly and release acrid compounds. It marks degradation rather than a safety boundary.
Refining raises it by stripping out free fatty acids and plant particles that break down early. Unrefined oils keep those compounds, along with the flavour they carry.
This is why cold-pressed mustard oil smokes sooner than a refined seed oil, and why cooks heat it deliberately before adding anything else.
Why saturation governs behaviour
Fats built mostly from saturated chains stay solid at room temperature and resist reacting with oxygen. Ghee and coconut oil both fall into this group.
Fats with many double bonds stay liquid and oxidise more readily, particularly with repeated heating. Their structure is simply easier to break.
That difference explains the traditional storage patterns, where ghee kept for months without refrigeration while pressed oils were bought in smaller quantities.
What ghee gains from being clarified
Making ghee removes water and milk solids from butter, leaving nearly pure fat. Removing the solids is what allows it to be heated much harder without burning.
The solids are browned before being strained out, and the compounds formed during that browning give ghee its distinct aroma.
Because the water is gone, ghee also transfers heat to food more efficiently than butter, which spends its first moments in the pan boiling off moisture.
How much fat the food absorbs
Frying temperature governs uptake more than the amount of oil in the pan. Food entering oil that is too cool absorbs far more, because the surface does not seal quickly.
Batters and coatings absorb more than bare surfaces, and porous foods such as bread or fritters more than dense ones.
A dish shallow-fried in a properly hot pan can end up carrying less fat than the same dish cooked slowly in a smaller quantity of oil.
Why regions diverged
The fats used in each region track what grew or was produced locally rather than any deliberate selection. Coconut in the south, mustard in the east and north, groundnut in the west.
Cooking techniques then developed around those fats, and dishes are calibrated to the flavour and heat behaviour of the one they were built with.
Substituting freely changes the dish, which is why swapping mustard oil for a neutral oil in an eastern preparation removes something the recipe was counting on.