Final answer:
A child with cystic fibrosis should consume more calories, have a high-protein diet, and supplement with fat-soluble vitamins due to the body's challenges in absorbing nutrients efficiently.
Step-by-step explanation:
The three dietary changes for a child with cystic fibrosis are focused on ensuring optimal intake of nutrients and managing symptoms associated with the disease. Firstly, increased caloric intake is often recommended due to the higher energy requirements and malabsorption issues. Secondly, a high-protein diet is beneficial, including foods such as fish, chicken, dairy products, legumes, or nuts. Lastly, the supplementation of vitamins, especially fat-soluble vitamins like A, D, E, and K, is important due to the difficulty these patients have in absorbing fats properly.