Nouns ending in -tion are feminine.
The suffix forms abstract nouns of action or state.
Is alimentation masculine or feminine?
l'alimentation
The rule behind it
99.8% of -tion nouns are feminine
In context
Nous savons comment l'alimentation influence la croissance.
We know how food affects growth.
Le câble d'alimentation est-il branché au mur ?
Is the power cord plugged into the wall?
Elle fait attention à l'alimentation de son enfant.
She is careful about her child's nutrition.