Yes, I recognise the problem. I recently found some packets of beansprouts in Sainsbury's. Only 0.7g carbs per 100g! I thought it was my birthday, even though they do weigh quite heavy. Just round the corner I saw packets of beansprouts in Morrison's, apparently identical except 1.6g carbs per 100g. Incidentally the Morrisons ones come out higher in protein too.
I buy a lot of cheddar cheese and the different brands vary between 0.1 and 1g carbs per 100g. Can this be true? If it were, of course I would buy the brand that is lower in carbs. I notice too that in his book Dr Bernstein attributes a lot more carbs to cheese than are shown on the packets here. Is this because the American cheese contains more carbs, or because we should not trust what we read on packets?
It seems to me that all this uncertainty is designed to torture us, and the harder we try the more painful it gets. Unreliable meter readings, unreliable food labels, inaccurate A1c tests ... I suppose it's better than blissful ignorance and the Eatwell plate?