I like TPM's suggestions too, the breakfast egg muffins are great! Get those veggies and fruits in your boys too, I'm sure it goes without saying but some may not realize that with all that protein they take in they WILL be constipated. Hydration plays a big part in keeping the GI moving too, and it will help so much with keeping their skin clear. All this advice about hydration, if it was already stated, forgive me, but refraining from what makes you dehydrated is another part, and the biggest culprit of that is sugar. Soda especially. Ever drank pickle juice? It's very hydrating. Vinegar is the key. Vinegar, get ACV with the Mother, mix with honey and lemon as well. Helps with electrolytes without Gatorade. Fresh limeade is great, sweetened with stevia.
If your son is feeling miserable on this diet of added protein then they will not stick with it. I went on a high protein diet for a couple years, cut out all sugar and non veg carbs, so kind of know from experience of what can go wrong, and how it feels, lol! Macadamia nuts are another protein that helps with digestion. Do salads, like Taco Salad or Cobb Salad (loaded with turkey and bacon)! Those are good mixes of protein with veg.
Smoothies help my boys alot to get a variety of nutrients....Get bags of raw spinach, blend it all up in a blender and pour into ice cube trays and freeze and store in a gallon ziploc, then pop in a spinach cube every smoothie, it's quite flavorless! Whalah! Veggies! For easy access, I keep all smoothie items on the door of the freezer (blueberries, strawberries, mango, frozen bananas -(were about to turn brown before used and peeled and wrapped in saran), pineapple, peaches, coconut chips, etc. Also, peanut butter POWDER is a great mix in for creamy flavored smoothies.
I bought a Ninja/Nutri Bullet single smoothie machine so my boys could use it - and will easily travel to college! Buy a bulk pack of insulated to-go cups at Sams club or similar with lids, plus straws and smoothies on the run every day out the door, so easy!
Also, bone broth. Don't get me started. Love it. Fish . Mmm. Good protein sources. Find meat sources that don't have tons of nitrites/nitrates/ additives. I really don't want my boys to turn into some kind of he-man science experiment. My 16 year old is very fit, muscular/strong build and good skin. To us, it's more of a marathon. Not a sprint.