I need some advice. Our Christmas celebration this year will include a teenage girl with

[Me.]

2. Here's Some Info For You

Dark chocolate is especially good, but I'm pretty sure she can eat most anything as they function better with a high calorie diet.

https://www.medicalnewstoday.com/articles/326511.php#dark-chocolate

Whether eating at home or away, here are some simple tips:
• Drink whole milk and milkshakes.
• Add extra butter or olive oil to foods like potatoes or pasta.
• Use regular (not diet) dressings on salads or vegetables.
• Eat burgers with bacon and cheese.
• Eat pizza with extra cheese.
• Add cheese to sandwiches.
• At breakfast, eat omelets with extra cheese and ham or bacon.
• Top salads and sandwiches with avocados or guacamole.
• Eat calorie-rich desserts such as ice cream, pudding, and cheesecake.
• Top hot chocolate, pudding, and other desserts with whipped cream.
• Avoid diet foods – anything that says nonfat, low fat, reduced calorie, or light/lite on the label.
Besides eating high-calorie meals, it's a good idea for guys and girls with CF to carry some high-energy snacks with them; try trail mix, nuts, packets of cheese crackers or peanut butter crackers, and veggies like carrots or celery with small containers of dressing that don't need to be refrigerated.
• https://kidshealth.org/en/teens/cf-diet.html