Does a short walk after meals really make a difference?

Yes, and it is one of the better-evidenced small habits. Ten to fifteen minutes of easy walking starting soon after eating measurably reduces the post-meal blood sugar rise, because contracting muscle takes up glucose with relatively little insulin. It also helps digestion and reduces the post-lunch slump. The effect is largest after the biggest carbohydrate meal, which in most Indian homes is dinner. It does not need to be brisk — an easy stroll is enough, which is what makes it sustainable when a workout would not be.