Question about an obscure Vietnam-era film involving... force-feeding lasagna?

Ok, I caught part of this film on Cinemax about 40 years ago and for the life of me have been unable to find it. It was a military film with guys in a mess hall, and one of them is complaining about the food. A tough sergeant forces this private to eat a bunch of lasagna and then punches him in the stomach to make him get sick. Perhaps it was about a young Jim Davis before he created Garfield, I don't know, but this one has bugged me for a long time. I'd love to know what this was, or if it was just a weird fever dream. Thanks.