WHY MY BABY NOT GAINING WEIGHT?

Hi..I have 9 months old son. His birth weight is 2.2kg. His current weight is 7.4 kg. He is on breastfeeding and solids.

His diet is as follows:

3 meals a day and 1 snack.

For meals:

dal rice with ghee, egg with rice, multi grain cereal, oatmeal cereal, lotus seed powder with nuts, vegetable rice, fish occasionally

snacks: fruits, yogurt
His breastmilk intake is also good. His milestones and activities are good.

So why is he not gaining weight? Please advice?