Well, not exactly. It so happens that the various tissues present in one’s body undergo cell replacement at different rates, so it really is rather contentious to say such a thing - especially since the above statement gives the impression that we spontaneously regenerate - rest assured that the average human being would never undergo such a miraculous change. In fact, there are certain tissues that never replace cells at all - the neurons in the cerebral cortex, for instance, are permanently irreplaceable after birth. Cardiomyocyte heart cells,however, are replaced as a gradually reducing rate as we age, averaging at perhaps 1% per year at the peak of our youth, and gradually reducing to half the rate by age 70 - but even so, that would mean that the average person would have had less than halftheir cardiomyocyte cells replaced in their entire lifespan. But of course, the cell replacement rates for a mutant could be a completely different story…
There is one particular type of tissue that undergoes full cycle of cell replacement in approximately seven years, though - fat cells have a replacement rate of about 10%. So I suppose you could amend the statement to say ‘Every seven to ten years, our bodies undergo a full replacement of every fat cell. Every seven to ten years, our fats disappear.’
…It does make for a different atmosphere, however.
This blog is so many things that I love all wrapped into one; I can barely contain myself.