Welcome Dan. That might have been me. I told my doctor I would lose 50 pounds in 6 months and he kinda chuckled me off, and said "the only way you are going to pull that off is if you cut out every single carbohydrate" - so I did, lol. But as that 6 month checkup was getting close, I was stalled at 40 pounds down. So I started backing off the butter, trimming the fat from my steaks, and removed dairy altogether. I broke my stall but quickly stalled again, and I was having diarrhea. Then when I did my labs I had ridiculously high triglycerides and the doctor wanted me to be a vegetarians instead. One of my theories regarding my trig problem was my macros. I was basically eating a no carb, low fat, high protein diet and I thought maybe it was gluconeogenesis at work. I was wrong and did figure out the issue. But, to fix my macros and make it ketogenic again, I had to up the fat. I returned to using liberal amounts of butter, started eating the fat on my steak, added back cheese, and my stool returned to normal. The diarrea went away.
Since then, I've heard two things. 1) That cheese is a natural constipater. And 2) in the book Strong Medicine that I uploaded, there is an account about how Stefansson went on a diet of lean meat, and had diarrhea and digestive discomfort, but when he started eating the fat his issues went away. When I read this it reminded me of my own experience.
That sounds like my diet. Chicken and certain cuts of pork (consumed less often on my part) can be lean but it's not the end of the world, you can always add fat to those meals through other means.
So we know things were working as expected. I've heard that the heart beats better when running on ketones, and this stonger beat worries some people. You just have to get used to it.
Tis the season for viruses here in the U.S. Could you have caught a bug? It just stands to reason that something changed at the 10 week mark.
That is common advice, and I hear it from Dr. Anthony Chaffee a lot. The thinking being that if you eat too much fat you won't have enough bile in your gall bladder to break it down, so it will result in loose stools, and you should dial back the fat a bit. But if you didn't increase your fat at the 10 week mark and things were fine prior to that, then I wouldn't suspect this is the case.
I will say that during my first 2 months of strict carnivore, I would oscillate back and forth between stool that was hard as rocks, to utter liquid, and I could never predict which was next. This lasted for 6-8 weeks before things returned to my new normal.
What kind of magnesium and what is the dosage? Certain types of magnesium will cause loose stools.
I eventually developed severe cramping as well, which was from an electrolyte deficiency. I now take a magnesium complex every day, but I've made certain to find a product that contains forms of magnesium not notorious for causing people to explode on the toilet.