"I eat food."
Translation:Eu como comida.
I agree your sentence should also be accepted. But if a person says just "I eat food" you hardly ever see "eu como alimento" — "comida" is more frequently used. We use alimento in these instances:
- If the speaker gives additional information: "I eat healthy food" = "eu como alimento/comida saudável".
- When you say "comida", you may sometimes refer to food which is not junk. (No almoço, gosto de comer comida = at lunch, I like to eat food -- not sandwich, bread, cookies or anything else)
- "Alimento" is somehow more formal, then you'll hear that on TV programs or by doctors, nutritionists....
"Comido" = eaten and is not a noun like "[a] comida" = food.
Comido is the past participle of the verb, "comer" = to eat.
comido adjective / past participle, masculine
eaten past-p (often used)
Nunca até agora, na história mundial, tínhamos comido tanta carne quanto hoje.
Never before in the history of the world have we eaten as much meat as we do today.
"Comida" can also mean ingested.
O composto, utilizado para tornar visível a tinta em papel termosensível, é comido por homens ao manusear as notas fiscais e depois tocar sua boca ou ao manipular de alimentos.
The compound, used to make ink visible on thermally sensitive paper, is ingested by men when they handle the receipts and then touch their mouths or handle food.