oh, now i see what you meant by 'the criteria is whether or not babies become malnourished', ilovemountains, sorry i hadn't twigged that before. reading the thread back, i see you mean the criteria for purees having 'worked for years'.
i disagree, however, in the west very few babies are in danger of malnourishment so i think our criteria for weaning 'working' has to be different. otherwise you could feed a child until they were the size of a beach ball and by your criteria it would be a huge success. i think we should be looking at obesity, diabetes etc.
there's nothing btw to advocate BLW there either yet, i should say, but then we don't live in a society that automatically assumes that BLW 'works', hence the heaps of research being done at the moment. whereas puree 'has worked for years'... the same years as a diabetes and obesity bomb has hit the west. (am not arguing that correlation = causation btw, just that is might be worth looking at).