With your birth details, only quite a limited analysis and study can be done for your child and with the child's birth details and his chart analysis many other details can be found out.
As per your chart, your son would be highly energetic and he could be ignoring food for other activities. You may try by reducing his other options available around him which distract his mind from having his food.
It would be pertinent to say that a professional medical as well as dietician's advice should also be taken for him to have a healthy diet.
Sagittarius ascendant with ascendant lord Jupiter posited in the tenth house conjunct fifth lord Mars, Sun, Moon and Mercury. The fifth lord of Divisional Chart 7 is Venus posited in the eighth house conjunct Jupiter and Moon posited in the fifth house in D7.