Cooked and cooled rice or potato does change in one interesting way.
When starch is cooked, it absorbs water and becomes easier to digest. When it is cooled, some of that starch reorganises into a form that resists digestion. This is called resistant starch. It can reach the large intestine and be fermented by gut bacteria.
This does not mean cold rice or potato becomes a health food without limits. Portion still matters. The rest of the plate still matters. A bowl of cooled rice with vegetables, dal and curd is different from a large fried potato snack.
Indian meals already use cooked and cooled starch in some forms: leftover rice, curd rice, lemon rice, potato chaat or tiffin meals. The smarter approach is to pair these with fibre and protein. Add dal, sprouts, vegetables, curd, peanuts or salad. Avoid turning the idea into an excuse for oversized portions.
People with diabetes should not assume cooled starch is automatically safe. Personal blood sugar response can vary.
The useful lesson is that cooking changes food structure. Resistant starch is one more reason to look at preparation, not only ingredients.
Cooling rice or potato is a genuine trick, not a diet loophole. It changes the starch a little. It does not change the plate rules.