When you next whip out your supermarket discount card to save 50 cents on hot dogs, beware: The store may put that information online to sell you tofu.

So hopes Watertown (Mass.) startup SmartMouth Technologies. The key is capturing consumers' purchasing data from supermarkets, then giving shoppers nutrition report cards while suggesting healthy alternatives. Low-fat graham crackers instead of Oreos, for example. And a dose of self-loathing on the side, please!

SmartMouth's supermarket clients ship data on purchases to the startup (deleting shopper-identifying data other than club-card numbers). Cardholders visit SmartMouth.com and enter their number to be critiqued. Stores are hoping you'll buy the tofu, since nutritious food is more expensive. As Pink Floyd put it: If you don't eat your meat, you can't have any pudding.

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