I can't believe this is still a problem. I used this app before Xmas but couldn't log in on the Android app. I asummed the problem would have been fixed by now but it still doesn't work.
In a word - rubbish.
Hmm, let's think... could it be that the problem is with your phone and not the app/service since the vast majority of users appear to be able use the app, short of the occasional glitch.
Yes, sometimes, in areas of poor connectivity or high traffic, I get the occasional error but on the whole the app. has worked reliably for the last three months.
Have you tried un/re-installing the app or clearing the data? Try Settings | Applications | Manage Applications, scroll to the Calorie Counter application and tap it, select the "Clear data" button then the "Clear cache" button. This should remove any invalid data on the device for the app, it should now start afresh at the next launch.
Have you also tried accessing the FatSecret website from the device's browser to confirm that your device/service provider is not blocking the address somehow?
What about contacting tech. support, they helped me very promptly with a minor issue I had?
If all else fails, backup your data and factory reset the device.
Your criticisms would seem to be... "In a word - rubbish".