Explanation
In Brazil, offering food is a warm gesture of hospitality and affection, especially when meeting a family. Refusing it can be seen as rejecting the host's care and generosity, potentially causing offense. It is customary to accept at least a small portion to show appreciation and respect.
Local Tip
If you are full or have dietary restrictions, accept a small amount and take a few bites, or politely explain with a smile that you have a health issue, but never flatly refuse.
How it compares elsewhere
Refusing food is generally polite if done with proper excuses (e.g., 'I'm full'), but outright refusal can be awkward; it's better to leave a little on the plate.
Refusing food, especially in a family setting, is considered very disrespectful as it implies rejection of the host's hospitality.
Refusing food can be seen as impolite, but it is more acceptable if you offer a polite excuse and compliment the cooking; hosts often insist you try a little.