Most TIM are conductive metals like silver, it shouldn't be lethal, but having too much of that in your body isnt ideal, see this link: http://en.wikipedia.org/wiki/Argyria
If you ate ceramique however, it should just go through the digestive system and get expelled via defecation(pooping), and nothing would happen for the most part.
if you plan on overclocking I would start with 2 monster drinks and see how that goes while mowing the lawn. If you feel dizzy just stop mowing and go take a break and eat some more thermal paste