Paul wrote this:

If one says just "I eat food" you hardly ever see "eu como alimento", but "comida" is more frequently used. We use alimento 1) if one gives additional information., "i eat healthy food" = "eu como alimento/comida saudável". 2)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) 3) "alimento" is somehow more formal, then you'll hear that on TV programs or by doctors, nutritionists....

comida = food
alimento = nourishment

alimento, like nourishment, has a broader definition.
alimento pra alma = nourishment for the soul
Plantas, fungos e bactérias também precisam de alimento = Plants, fungi and bacteria also need nourishment

It's accepted now, even preferred.

In Portuguese, as in many other languages, masculine is the inclusive/non-marked gender, and feminine, by contrast, is the exclusive/marked one. It means that when a word has both a masc. and a fem. version, the masc. one will be generic and will embrace both masc. and fem. entities.

• Ela foi o primeiro habitante daquela ilha.
  She was the first inhabitant of that island.

• Ela foi a primeira habitante daquela ilha.
  She was the first female inhabitant of that island.

So, if you don't want to specify any gender, use the masculine form; if you want to specify the female entities, just use the female form; if you want to specify the male entities, you have to make it explicitly, with the aid of another words.

• Ele foi o primeiro habitante homem daquela ilha.
  He was the first male inhabitant of that island.

You could say "As pessoas", which is "people".