It's a play on the term "syntactic sugar": Too much syntactic sugar leads to syntactic diabetes. And syntactic sugar generally refers to language features that allow you to write things in neater ways. It is always possible to "de-sugar" such constructs by writing them in a more basic way, which is usually less neat. Examples would be e.g. list comprehensions, for .. in syntax, x += 1 etc.
It refers to the fact that there are many syntactically-equivalent ways to express the same code. Slide 11 shows expressions that evaluate to the same thing.
Thanks, that makes sense, I read the fooN functions but didn't make the connection with "syntactic sugar".