Keto diets are notorious for this -- some people are, apparently, genetically unsuited to extremely low carb diets and their body responds by ballooning cholest

Keto diets are notorious for this -- some people are, apparently, genetically unsuited to extremely low carb diets and their body responds by ballooning cholesterol levels and possibly some other issues (has been a while since I read about it). So they recommend that people getting on that particular diet do both self-monitoring and blood tests. You could be experiencing some form of that. A lot of these ideas are very poorly studied and may be missing negative effects that occur in a minority.