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Caffeine sure, but sugar (glucose) is a vital fuel for your cells, particularly the brain: no glucose, no life.
Of course it's very easy to eat too much sugar considering modern foods and diets. But I don't think you can classify it as a "drug".

Yes I agree, but funny enough sugar was actually listed in a video about this topic that I watched too. The reason why is that some studies say that sugar is as addictive as cocaine, and the whole point of that video was to surprise people with facts that everyday things can function like drugs inside the body.
But I didn't add it to my post here, because I agree with your opinion that it's a vital part of life and doesn't really count as a drug.

True! Caffeine is the world's most popular legal drug!