Is it ok to replace breakfast for a Whey Protein Smoothie?!

no is not unhealthy. However I suggest you not to add the whey protein to the smoothie. In order to absorb all the nutrients from the fruits, fruits should be eaten ALONE. After a smoothie (made only with frozen fruit and fruit juice or water) wait about 30 min before eating anything else, including your whey proteins. After about 30 min, your body will have absorbed all the nutrients from the fruit and you can go ahead and have your whey protein drink (mix the powder with water (or milk) and eventually add 2 drops of vanilla extract, but this depends on your whey protein's flavor...., you don'tnecessarilyy have to add any extraflavorr to it....). I totallyunderstandd your mentality, I had a similar mentality when I was 15. Maybe you don't need to use whey protein now, since at 15 you are not supposed to lift heavy weights.... Most likely, now you can get all your nutrients from "regular" foods. Then when you'll start working out lifting heavy weight, you can integrate your diet with "extra" sources. For a short period I used whey protein when i was 15 or 16, I don't think it harmed me, but looking back, I think it was unnecessary.... It's your call.Perhaps ask your school GYM teacher what he thinks about it, based on the training your are doing. I don't know exactely what exercises you do. However, as general rule a 15 y.o. guy shouldn't pump too much iron (and I totally agree, even dough I've been 15 too.....)

not unhealthy at all... you are getting a big boost of whey protein.... and your getting some fruit.. thats pretty much a complete breakfast.. thats not bad at all...

no worrys...

Try eating a banana with that!