I never once heard him mention endogenous opioids. Besides, even if that was the thrust of his arguement, it still isn't really casting sugars in a negative light. You can have an endogenous response to anything. Its called classical conditioning.
For further reading (i'm afraid i can't find a link, sorry) there was a study done where a control group fed their babies an unsweetened formula, and the experimental group fed their babies a sweetened formula (i didn't know such things existed, but they do). Years later, the experimental group children were showing a much greater tendencey towards childhood obesity, as well as pickeyness at the dinner table.
Dr Who'shisface, is right, however, that we eat waaaaay more sugar, refined sugar in particular, than we ought to. It's a cultural problem, as is the amount of saturated fat we eat. I'm not going to jump on the bandwagon and say "people who eat meat are the ones who get cancer" or "if you like candy, you're pretty much a socially acceptable junkie".