You're already doing a great job by giving your 4-year-old a healthy diet with nuts and fruits. These are excellent sources of natural nutrients. Now that your child has started school and needs more energy and focus, it’s okay to consider adding a nutritional supplement if needed, but remember—no drink can replace a balanced home-cooked diet.

Hello I appreciate that you have not introduced any supplement until now and is focusing on nuts and fruits If your child is eating a balanced diet with fruits, vegetables, proteins, and grains, supplements are usually not necessary. Also, supplements should primarily come from food, not from drinks. Over-the-counter milk supplements are often marketing-driven and not medically necessary in healthy children. They are not a substitute for meals and may lead to filling up on empty calories, reducing appetite for actual food.

Consult with Pediatrician physically for further evaluation and treatment