No. The Main Goal is the Main goal and can be completed on its own without doing the side goal.
The Side Goal...it doesn't open until you've completed some of the Main Goal, but once it opens, it's yours to complete (or not) as you see fit. It's usually 3-4 steps of cooking lots of food for one prize at the end. Once in while, they give a prize after each step, but not usually. Again, the side goal has no effect on Main Goal completion.