My 9 year old, very sporty boy, is a little underweight, any tips on healthy weight gain in a child this age?

Actually, your son is pretty much even for height and weight. He's near the 50th percentile for both. Just give him calorie and nutrient dense foods, like peanut butter, avocado, good quality proteins, whole grains, fruits and veggies. Don't worry too much about the fat content as long as the fat is healthy fat, like peanut butter.

Well, as a former athletic coach, you can focus on more complex carbohydrates such as whole grains on the days before heavy exercise. If he has a big game or intense practice on Wednesday, have a large pasta dinner on Tuesday. These carbs will give him a big surge of energy the next day for that day's activity. You might also consider adding more good quality meat to his diet. That doesn't mean hot-dogs or hamburger, it means more chicken, fish, beef cuts, etc.

Provide him with foods that have a high calorie density, such as those given in the link below.

Good luck.

My daughter was put on an iron supplement for low weight it makes them a little hungry so you just add extra food on the dinner plate or at each meals its a healthy option. Some children that are under weight usually have an iron deficiency but as your son is fairly active and up and about i would suggest just a mixed supplement for kids

I was always considered underweight as a child and still am. As long as he's eating a well balanced diet and getting all his nutrients, don't worry too much. He'll be fine.

Clearly your son has a fast metabolism due to playing sports, this ultimately means he is burning off what ever you give him plus he is growing taller and the little weight he does have is dispersing elsewhere on his body...... You need to start him eating more pasta, breads, and red meat.... this does not mean rubbish this means healthy doses of these foods....... Remember unlike us adults they are continually growing so they often need plenty of food to put away so give him enough but keep up with the sports to balance it all out...... for children there is little else you can do....... I

I too have an extremely sporty 9yo, who plays about 8 sports and represents state for 3 of them and in national academy for 1. He struggles trying to keep a good balance of weight between growth spurts, and varying sporting needs, for surf life saving he needs to be leaner yet for rugby league needs to be more bulky..... i have got his diet down to a fine art, he is fairly tall not sure of height, but weighs a whopping 87lbs..... the thing is he has not a bit of fat, he has sixpack, chest muscles, back muscle and massive arms and legs.... It took us a long time to calculate his weight down and times we have to step back on carbs so he trims for surfing and such but normally his diet is really consistant, you just need to spend 6mths trying to balance his diet out to suit his needs.

Good luck and be patient it will happen just takes time...

I was too, cant really help it lol. Around 13 i got muscles so im sure he'll even out :) probably just has a high matabalism.

Pediasure is loaded with vitamins, protein, and calories. My pediatrician put my son on it because of his low weight. There are generic brands just as good.

Have him eat red meats like steak and beef. It has alot of protein

i'm not sure, but if you're really concerned you should ask a doctor...

He is nine. He is fine, if hes happy and not weak there is no problem.