1. If you are serving a guest with unhealthy food, the guest might take it rude.

If you serve a guest with unhealthy food, the guest might take it rude.
상황에 따라 둘 다 써도 괜찮은지 아니면 현재형을 쓰는 게 더 무난한지 알고 싶습니다.
2. Some people today still prefer the old traditional way of cooking.

Some people today still prefer thetraditional way of cooking.

Some people today still prefer the oldway of cooking.
old 하고 traditional 이 의미상 중복되는 것 같아서요..