Work out how many pints you can drink
and then work out what fraction of your body weight that is, and set that as your goal.

Much easier to achieve that way. "I drank 1/8th of my body weight in Guinness!!!" still sounds fairly impressive, and that's only 12.5 pints if you weighed 59.8 kilos (about 9 stone) - less if you're less and I assume you are.
( The Light in Chains don't touch the Pope's boner, Thu 17 Mar 2011, 10:08, 1 reply, 15 years ago)

If you only weighed nine stone
I doubt you'd be big enough to contain 12.5 pints of Guinness. (Let alone metabolise it without hospitalising yourself)
(LongJohnBaldry, Thu 17 Mar 2011, 10:28, Reply)

You just aren't trying hard enough

( sporters I’m sincerely gratitude to you, Thu 17 Mar 2011, 10:34, Reply)

trying hard vomiting often
( The Light in Chains don't touch the Pope's boner, Thu 17 Mar 2011, 10:54, Reply)