i travel for work all the time so i spend time talking to the TSA guys and find out what they're looking for.
the thing is, if you're heavily overweight, sloppy/lazy looking and have stuff like this (supps and protein) it kinda looks suspicious. but if you're in shape and it shows, they know you're not trying to pull a fast one. just a common sense thing.
when i'm on a long flight, i bring protein powder in a shaker and maybe some more in a zip lock bag. i ask for extra water on the flight and make my shake on the plane. i ususally have no problems with security.
as for pills, like someone else mentioned...leave them in their original bottles in your check in luggage and you're fine. hand carry only the stuff you really need to take while on the flight.
if i'm hand carrying everything, i have these small pill bottles that i just stick some scotch tape on...then i write the name of the supp with a sharpie. if they ask, i tell um what it is. if you hesitate, it looks suspicious... same here... common sense stuff.
anything solid is ok...pretein bars etc...i've even brought semi liquid stuff like yoghurt and spaghetti on. as long as you put them in a seperate bag and explain to them why you're bringing your own food, most times they're ok with it...just don't try to hide them...
just my 2 cents... | 
