Diets built around pulses tend to be high in dietary fiber without anyone aiming for it. The fiber is structural to the ingredient rather than something added to a refined base.
Fiber is what the plant is made of
Dietary fiber is largely the structural carbohydrate of plant cell walls plus storage carbohydrates the body cannot break down. Any whole plant food carries it by virtue of being a plant.
Legumes carry it in unusually high concentration, in both the seed coat and the interior. That is true whether the pulse is whole, split or cooked to a puree.
Refining removes it. White rice and refined flour have had the fiber-bearing outer layers stripped, which is why fiber has to be added back to diets built on them.
Split and skinned pulses lose some but not all
Removing the skin from a lentil takes away a large share of its insoluble fiber, which is why washed dals are gentler on digestion and cook faster.
The interior still carries substantial soluble fiber and resistant starch, so a skinned dal remains a meaningful contributor even though a whole one contributes more.
Soluble and insoluble fiber do different things
Insoluble fiber adds bulk and passes through largely unchanged, which is what the skins and bran layers provide. It is the component most associated with digestive transit.
Soluble fiber dissolves and forms a viscous gel, slowing digestion and providing material that gut bacteria ferment. Pulses are notably rich in this form.
Because Indian meals routinely combine whole grains, skinned pulses, vegetables and often a whole pulse as well, both types tend to be present in the same meal.
Adaptation explains the discomfort problem
A sudden large increase in fiber intake commonly produces gas and bloating, because gut bacteria ferment what reaches them and the population takes time to adjust.
Indian cooking includes practices that address this, such as soaking pulses, discarding soaking water, and using asafoetida and ajwain, which are traditionally associated with easing the effect.
Getting there from an American pantry
US supermarkets carry lentils, chickpeas and beans widely, and Indian grocery stores carry the specific split dals that Indian recipes call for. Neither is expensive relative to the protein it supplies.
Individual fiber needs and any digestive condition are matters for a clinician or dietitian. The general point is only that this pattern of eating reaches high fiber intake structurally, without a supplement in it.