Difference in sugar/flour versus alcohol approach?

In the overdrinking calls you seem to suggest that people not cut out drinking entirely if they have been drinking every evening but rather deliberately plan to drink less as a way to work on reducing desire (at which point they may end up cutting it out entirely). But with sugar and flour you recommend cutting it out entirely from the start. Is there a reason for the difference in approach? Is it because of the insulin versus dopamine responses?