You want to get up to 170? a 6 foot guy shouldn't have much bother doing that... no need to filll your self full of shit. Just have the work ethic and eat for it... 15 pounds isn't an awful lot and you're gonna get into a trap here - if you don't gain it naturally you you won't keep it natuarlly. 15 pounds isn't an awful lot to gain.

Stress your body with training... not upsetting the chemical balance of your body - get your protien and carbs in and train hard.

All there is too it.