You can probably add a bit of mass with bodyweight stuff, but to gain 22 lbs. of mass in 3 months on any program is pretty much unrealistic for such a short amount of time. That is, without steroids - using performance enhancing drugs is about the only way to gain that kind of weight in such a short time-frame, and of course, I wouldn't recommend that. Not to mention, going for a bike ride or run won't do anything but cause you to lose lean mass when done in excess, so those two things won't be good for any program where you're trying to gain weight. Reasonably, I'd say that without weights, you may be able to put on 3-6 lbs. of lean mass over 3 months as a beginner by doing bodyweight-only exercises, but that's providing you're training efficiently/effectively AND eating enough to gain AND that your body will respond well to bodyweight training alone. That's a lot of "ands" to factor in, so IF there's a way to get your hands on a barbell setup or some dumbbells, you'll greatly increase your chances of gaining mass. One last thing to remember, many of the bodyweight exercise gurus have also built their physiques using weight training, but may be making claims that they did it without weights altogether. It is MUCH easier to maintain mass once you have it than it is to gain, I could likely keep what I have with bodyweight exercises at this point, but would have a hell of a time gaining much, if anything at all. Thank you. I have read that I should get as much protein as I can. This person who has written it recommends me that I should buy a product which provides me protein. (He doesn't mention any brands) What do you think? Because he says that it isn't unhealthy, it is totally natural so it can't be harmful for my body in addition it will be extremely efficient. I have found one: 100% Whey Protein? They say it is the best.