It has often been said that during World War II, the nutrition levels in the UK under sternly enforced rationing laws, were higher than normal and people generally healthier. People could only get limited supplies, but nutritious ones, so didn't fill up on junk.
Although I was born under rationing, I don't really remember it. Didn't eat a banana or ice cream until I was about 8 or 9.
I'm not claiming the food was great, but it was nutritious.