Drinking the same amount of OJ will also make you fat. If OJ is too tart choose another type of orange like mandarin oranges. They're just as cancerous to rats and you can drink them like fruit punch as they are not tart.

The point is "gives rats cancer" bascially has no meaning. As another example chocolate is poison to dogs. Does that mean humans shouldn't eat chocolate foods or drink chocolate drinks?

Humans also eat plently of things that are toxic. Most spicy peppers are toxic if eaten in the quantities needed to induce by other substances in rats. So is vinegar, wine, cheese, pickles, ...

Ever heard of that super toxic dihydrogen oxide. About 360,000 people die every year from it, some with as little 120grams (1/2 a cup)