finicky eater

My son's girlfriends son is a finicky eater and will not eat protein. He is 18 months old.
He was eating mostly fruit, juice, cheese, pasta, yogurt.
We went away for a weekend together and he woke up with the shakes. His pediatrician said no more juice or fruit until he starts eating meat, eggs, beans (protein).
He will not eat meat when given a piece of chicken, pork, pot roast. He did eat a chicken strip a couple of times. He will eat a peanut butter sandwich and he will eat meatballs. I worry about giving him frozen chicken and meatballs all the time.
What do you suggest I try? I would like to keep food in the house that is healthy for him and encourage him to eat more protein.
Should we be checking his blood glucose?

[Renee Radenberg]

Protein comes from animal and plant sources. From animal sources it comes from all meats, chicken, fish, beef, pork, etc.; and dairy products such as milk, yogurt, cheeses, pudding, and ice cream. From the plant world there are complete proteins such as soy products:  tofu, soy milk, soy yogurt, soy pudding, and soy ice cream. Incomplete proteins you need to combine foods such as beans and rice, pasta with vegetables, peanut butter and bread, nuts in salad, and beans with pasta. You can try any of the above to get protein in him for each meal. Milkshakes (milk, fresh fruit, and ice cream) are also good for extra protein too. Protein is in the cheese, yogurt, and peanut butter sandwiches he is eating. All dairy products have complete proteins as in meats as far as protein goes; however, there is very little iron content. If you are concerned he is not consuming too much meat, then suggests a daily chewable children’s multi-vitamin with iron. Hoped that helped you.