Sandra, assuming your scales are accurate, a guess would be the weight
fluctuation represents fluctuations in fluid balance, due possibly to shift
in carb intake & menstrual cycle.

Did you have some carbs on Atkins and then none at all on Neanderthin (not
even berries in the pemmican)?

Had you been losing on Atkins or were you stable?

How do the amounts of calories on the 2 diets compare?

How are your clothes fitting?

Kathryn