I noticed this issue was closed, but after crafting the food it doesn't go towards the buff. Should I ask the nutrition mod author as well?

So I just tested this myself and the compatibility does work. I craft a Steak Sandwich which gives me Grain, Protein (3.0%) and, after eating it, the nutrition stats are updated appropriately.

Are you using the 1.3.2 version of Culinary Construct? Can you list out the steps you take in detail?

Closing this for now as I have not received a response and the compatibility works as far as I can tell.