Save calories and help charities with Foodtweeks app

Foodtweeks helps you cut calories and donates to food banks as a reward. Screenshot by Rick Broida/CNET

As long as it's in the figurative sense, nothing beats killing two birds with one stone.

Take Charity Miles, an app that donates money to charity whenever you exercise -- meaning you're not only helping yourself, you're also helping others.

Now comes Foodtweeks (Android