That would be 8,000 times a day. The measured figure is 19.
The claim has no traceable source, which is itself a clue. When researchers actually measured it — by giving 283 students clickers and asking them to record each thought about sex, food or sleep for a week — the median for men was 19 times a day, and for women 10.
The spread mattered more than the average. Individual men ranged from 1 to 388 thoughts a day, and the ranges for men and women overlapped heavily. The study also found men thought more about food and sleep too, which suggests the difference is partly about how readily people notice and report any need at all.