Take a look at the original sentence again:
Neil's day revolves around sugar, he anticipates
the pastry he will choose for breakfast, the candy bar he will eat for lunch,
and the ice cream he will have as dinner.
You chose to fix it the correct way:
Neil's day revolves around sugar, for he
anticipates the pastry he will choose for breakfast, the candy bar he will
eat for lunch, and the ice cream he will have as dinner.
A good way to fix a comma splice is to use a comma and a coordinating conjunction like for. When you use this method, you must choose a coordinating conjunction that logically connects the two main clauses. Because for means the same thing as because, it works nicely in the example above.