I've been thinking a lot about diet, and that thinking will eventually make its way into a blog post. But one thing in particular has always bothered me: since so much of the body's energy is devoted to maintaining temperature, shouldn't cold foods have essentially fewer calories than their warm equivalents?
There's not much out there on the subject, but I did find this paper by Paul Horowitz, of all people, a name the SETI fans among you might recognize, and the electrical engineers definitely will. (H/T to the summary I found here)
To summarize: yes, cold foods use up additional energy -- about 3.3 calories per ounce for a frozen yogurt. For cold foods that do not contain any calories (water, diet soda) a 12-oz can near the freezing point deducting a whopping... 12 calories. Yeah, you'd be better off at the gym, but in the mean time, now you have a good reason not to drink your Coke Zero hot. You're welcome.