"Я вживаю цукор."
Переклад:I use sugar.
"I consume sugar" isn't something we'd normally say in English, unless we want to sound more scientific. In a normal conversation it would sound a little odd.
"I use sugar" would normally be used when talking about cooking/baking. "I like the sweetness of this sauce" - "I use sugar"
"I eat sugar" would mean in general, so you are not on a sugar free diet.
"I have sugar" can sometimes be used to mean eat. "Do you like unsweetened coffee?" - "No, I have sugar (with it)"
"I have sugar once a week" = you mostly eat a sugar free diet, but once a week eat something sugary.
"I have sugar on cereal"