Explanation
In Spain, especially when meeting family, refusing food offered by a host is considered impolite because it can be interpreted as rejecting the host's generosity and hospitality. Spaniards take pride in offering food as a gesture of warmth and welcome, and a refusal may cause offense or make the host feel their efforts are unappreciated. It is better to accept a small portion or at least taste the food to show respect.
Local Tip
If you are full or have dietary restrictions, accept a small amount and compliment the host, then politely explain your situation after the first bite.
How it compares elsewhere
Refusing food is often polite to avoid burdening the host, though it can be nuanced; a simple 'no, thank you' is acceptable.
Refusing food is generally considered rude as it is seen as rejecting hospitality; hosts may insist multiple times.
Refusing food can be seen as impolite, but it is acceptable if you offer a polite excuse and compliment the host's cooking.