I order Gu gels and Clif Bars from Wiggle every once in a while.How do you go about getting your drinks and gels etc?
Slightly strange question in the land of the combini, but FWIW...
Gels are available in any large-ish drug store, at least in the suburbs. Same for sports bars, although the brands/contents are different. Combinis often (but not always) have gels/bars, too, but if I'm there anyway I'd usually get an onigiri or something instead.
For sports drinks, Pocari Sweat/Aquarius are ubiquitous, and presumably contain the salt/water/sugar needed (not being an expert).