Explanation
In Russian culture, especially when meeting family, offering food is a deep expression of hospitality and care. Refusing can be seen as rejecting the host's generosity and may offend them, as it implies distrust or lack of appreciation for their effort.
Local Tip
Always accept at least a small portion and compliment the food, even if you are not hungry.
How it compares elsewhere
Refusing food is generally polite if done with proper excuses, but accepting is still appreciated.
Refusing food from a host, especially in a family setting, is often seen as an insult to their cooking and hospitality.
Refusing food is considered impolite and may hurt the host's feelings; it's better to accept and eat a little.