Learn Portuguese (Portugal): Nós comemos pouco açúcar.

Pouco (little or not much) is a quantifier that changes its ending to match the noun it describes. Here, it describes açúcar (sugar), which is a masculine, singular word. If we were talking about a feminine word like soup (sopa), it would be pouca sopa.

Does pouco mean "a little" here?

No, by itself, pouco means "little" (meaning "not much"). If you want to say "a little" (meaning a small positive amount of something), you use the phrase um pouco de. For example, um pouco de açúcar means "a little sugar".

Is comemos regular in the present tense?

Yes! It comes from the verb comer (to eat). For the nós (we) form, regular verbs ending in -er drop the ending and add -emos, giving us comemos.

Why does the word açúcar have an accent mark?

The acute accent on the ú tells you to put the stress on that middle syllable. Without it, the normal rules of Portuguese pronunciation would make the stress fall on the final syllable.