Wow, El Reg being written by commentards
What an appalling article? I expect comments, after a piece, along the lines of "This device isn't useful to me therefore everyone who is interested must be a raving idiot" but I don't usually see the author firing the opening shots.
Quite apart from the examples given above, long distance running would be a perfect candidate for this technology, if not the product itself.
Working on the basis the sensors actually work, if they could be placed into a sports bottle they would be brilliant. I do ultra distance events, mountain marathons, that sort of thing. Whilst you are required to carry some emergency supplies you are fairly dependant on whatever the race organisers supply at the feed stations for most of your needs.
So I spend months training, watching what I eat and drink, analysing how much I sweat under certain conditions, formulating feed and hydrations plans but then have to take whatever is available (usually very little by the time I get there) and hope it is okay. I can control this a bit by carrying salt tablets to drop into water etc. but I'm constantly getting it wrong and ending up either dehydrated or (worse) washing all the salts out of my system by drinking too much water and then coming down with cramps.
A bottle that can analyse exactly what I've consumed and send an alert to my phone with a recommendation of what to collect at the next feed station would be an amazing thing indeed. And if the number of on-line stores, brands, products etc. cropping up all the time is anything to go by this is a large and rapidly growing market.