my child is 6 years old. he eats well but doesn't get weight. he is 16 kg only. how to gain weight to him

A. his, weight is borderline weight. Ghee, yoghurt, butter, soya, eggs, paneer, black grams, dates, all pulses, rajma, chickpeas, peanuts- jaggery chiki , dry fruit and nuts, fruit like banana, chikoo, grapes, mangi, custard apple will help to increase his weight