You'll start to turn orange if you eat too many carrots, continue to eat more over a period of time and you'll die. Also, poisoning is the same as overdosing, it's just that poisonous plants have a very low overdose level. Why do you think drinking 2 gallons of water in an hour leads to water toxicity aka water poisoning?
You wont die of carrots, the body regulates how many nutrients are absorbed. As we saw earlier in the thread, if you take 1g of powdered Vitamin C almost everything is absorbed. If you take 13g, almost nothing is absorbed. The same goes for other types of nutrients. The bowel does not simply absorb everything you shove in your mouth.
Water and electrolytes are the few exceptions to the rule because the molecules are too small to be regulated by the bowels, and just pass through. The filters of the bowels are on a larger scale to regulate the bigger and more complex vitamins, fibers, fats, and nutrients. This is why it is possible to die from drinking too much water, but not die from eating too many strawberries. The body is more concerned about you getting the exact ratio of nutrients to match its present needs than stopping you from doing something stupid like ignoring your instincts to stop drinking down gallons of water.
As per poisons like cyanide and hemlock, and poisons that physically destroy the cells of the gut to punch its way in and destroy everything in its path, that's not really in the realm of discussion.