A mobile-phone version of this site would be useful for dealing with those inconsistent labels mentioned below. It comes grace of the US government and though pounds and onces aren't the imperial kind (I think) you're given lots of weight options, including metric of course, and lots and lots of food info about just about everything. It is search-based rather than list based and seems to do the trick nicely. I tried bananas, maple syrup and tuna canned in oil. (No - it's not some mad dish I'm conjuring up). It provided all the info I needed plus some. Definitely worth a visit.
Over here the new thing is Five Portions of Fruit and Veg a Day. Check it out here. This is the total opposite in style - it keeps things short and sweet and there is a useful list of of "portion" samples. It could do with a portion-calculator and a search function I think.
And failing that there is also the option of popping a few newly-arrived pills and getting them to do the job for you - for smoking and for weight control.