I'll have a go. First thing, you say "bottle," singular. So you're going out with one bottle, meaning you probably aren't riding more than an hour or two. You don't need protein
during a short ride like that. You might consider putting some carbs in that bottle. If you did that, you might consider adding a little protein. A 7:1 carb/protein ratio has been proven effective for riding however far.
After the ride, you might consider a 4:1 carb/protein beverage of some sort. Though if I finish at home, I'll just do the protein with a little sugar in it and then have a carby dinner soon after, getting most of my recovery carbs from that.
It all depends on how hard and long you went and if you're going out hard again tomorrow. The very best thing is to have 1.5g of carbs per kg body weight in the 4 hours following your ride, and then protein in about that 4:1 ratio. But how you consume that will depend on your experience and goals.
Hemprider hasn't yet figured out that we burn protein when we ride hard. The harder we ride, the more we burn. We actually burn it. Burn it right up, like gone. If your body can't get it from your food, it will get it from your muscles. Give him time. He'll figure it out!
Everything you ever wanted to know about fueling for bike riding is here:
http://www.hammernutrition.com/za/HN...URANCE_LIBRARY