Dude, what are you asking? Your post isn't very clear.
Here's my take on things. As far as health goes, I think you should aim to maintain an overall healthy lifestyle. In my opinion that's a balance of a clean diet, cardio work, flexibility, weights and recreational sports. I personally follow cycles of bulking and cutting to use gym vernacular and consider myself to be more of a bodybuilder than the average person looking to be "toned" or generally fit. I eat a high calorie high protein diet (around 3500-4000 calories a day) and increase my bodyweight around 10kg every 6 months. I then lose around 5Kg through dieting and repeat the process again. I maintain my health by following what I said above, keeping the approach balanced. I rarely drink alcohol, don't smoke, don't take drugs and don't eat fast food. I believe these things are more detrimental to your health than bulking up. So in essence if you follow a sensible plan you'll be fine. Bodybuilding is a very healthy sport when done correctly. IMO it will only make you healthier and put you in a better position to maintain a class 1 medical. Of course i'm talking about drug free bodybuilding. If you're thinking of using steroids to get big I'd suggest looking for another career before you start flight training.
Not sure how creatine and other supplements go, I don't take them. You'd have to check with your DAME.
As others have mentioned, some airlines use the BMI menthol of determining your health and medical condition. This won't effect you now as you're a student pilot but it's something to consider for the future. I think it's a vastly flawed system, as in good shape at 6'1", 90Kg and 12% body fat it classes me as overweight. Sometimes I think these systems are thought of by people who have absolutely no idea. Good luck!