[ Nigerian Lager (Guinness) is the staple of any sensible man's endurance race.
Quite so, delicious and nutricious, not too fizzy, substantial enough to substitute track food, smooth, creamy, full-headed and ultra refreshing (if properly chilled) - and not particularly mind-splitting the following morning. I can even live with the merde-noir for the following few days, in exchange for all it's benefits.
Dave, you got it right when you proclaimed, "Look after your Guinness and your Guinness will look after you". This time next week it'll be starting to pass through!