How to gain weigh in a healthy fashion

Our doctor has said my daughter needs to gain 22 lbs.  She eats very healthy, well balanced foods (possibly low on carbs).  She is very active.  Our doctor gave us no idea on how to accomplish this.  I was told by someone else she needs to take in 250 - 300 grams of carbs per day.  Is there a list somewhere of foods and there carb value.  Also which are good carbs and which are empty carbs?  Gaining 1/4 of her body weight seems excessive.

[Renee Radenberg]

Would you please state your daughter's age so I can answer your question properly. Thank you.

[sportsmom20]

Absolutely,

My daughter is 12 (she will be 13 at the end of March).  She eats fruits, vegetables, meat.  An idea of the kind of lunch she will take to school is whole grain bagel with herb and garlic cream cheese, grapes, apple, carrots and dip, cheese,  pate and crackers, water and usually one or two of either granola bar, fruit source bar, a couple of cookies, almonds in container something sort of snacky.  They have 2 nutrition breaks at school instead of 1 lunch. so it sort of breaks it up

[sportsmom20]

Sorry, I rushed my answer because said daughter was leaving for a track meet.

breakfast is usually toast with peanut butter and banana or a bowl of cereal and apple - she doesn't like yogurt or orange juice - likes apple juice, strawberry milk(not chocolate) or water

lunch variations - tuna sandwich, chicken wrap, bagel w cream cheese, cheese/kielbossa/pickles/crackers
veggies - carrots, cucumber, red yellow or orange peppers, lettuce in wraps, celery in tuna
fruit - strawberries, pineapple, oranges, apple, grapes, peaches, plums (banana doesn't make it to school well - that is a home fruit

I had heard nuts like almonds and walnuts were high in good carbs, so we have been adding those.  I had also heard that chocolate milk was good, she doesn't like chocolate so I added strawberry.  We will fill an empty water bottle with it to take to school.

dinner is a normal meal - meat (any type - steak, roast, pork, chicken) she doesn't like pizza, doesn't like rice, not big on pasta will eat baked, mashed or french fried potatoes, likes most veggies including beets, zucchini, yams, squash which a lot of kids don't like.

I thought for a kid who is growing into her height that his announcement that her BMI was 14% and he wanted her at 18% which meant she needed to gain 22 lbs wasn't really the best thing for her.  She could absolutely gain some weight, but as I said earlier I feel that 1/4 of her body weight is too much.  But I am open to adding healthy foods to promote weight gain.  

I appreciate any help or insight you can offer

[Renee Radenberg]

Thank you for answering back and the food history which was great. Your daughter eats very healthy and she is very active. Her weight is on the 10th percentile and her height is between the 50-75th percentile for her age (This is based on 13 years old due to becoming that age in 30 days). Her weight is still on the growth chart which is good. If her height was based on adult measurements she would need to gain that much weight, however, she is still a child and should be having her weight and height charted on the growth charts. She does needs to gain some weight. She is entering puberty and will be gaining weight as she becomes a 'woman'. If you increased her portion sizes of her food and gave her milkshakes (milk, ice cream, and banana or other fruit blended together) that would give her additional calories and protein for weight gain. Hoped this helped you.