Industrial sugar is a poison in any quantity.
As for anything being a poison in certain quantity ... True. I am used to say that we humans have a bucket inside and we don't know where the edge of this bucket is. You can fill it day in day out with a poison and you don't notice its ill effects. But, when the stuff comes over the edge, it's too late.
We are way too careless when it comes to our health and healthy living, food included.