but to posit a complete race of people as "giants" is far fetched. There is no archeological evidence for such but medically seems ridiculous too.
I think, from memory, the tallest race/tribe on the planet is a tribe in Africa where adult males average 6' 1" (I also think some locations in Montenegro are around this too). Now the avergae adult male on the planet is about 5' 5" or so. The standard deviation of this population is probably only two inches or so. Thus even the 6' 1" average is probably some 4 standard deviations away. Once you get to say an average of 7' you are 10 sigma away. This is a miniscule probability.
Now this isn't an airtight technical argument but I do think it has some validity when you combine it with the lack of archeological evidence for such giants.