Controlled weight gain is often conducted with the involvement of a Registered Dietitian who educates a person about healthy food choices.
They are able to provide comprehensive nutrition education and guidance. A RD is uniquely qualified to provide evidence-based advice on healthy food choices to promote weight gain in an individual. They can assess an individual's current eating habits, identify areas of improvement, and suggest meals that are both nutritious and calorie-dense to ensure the individual is able to gain weight in a healthy and sustainable way.
Hope this helps! Have a nice day. :)