According to Dr. Robert Cywes MD Ph.D. who is a surgeon who does many bariatric surgeries, and is himself a bariatric surgery patient as well as a carnivore.
The formation of gallstones has nothing to do with dietary fat intake. This is a common misconception not only with patients but with doctors in general.
The doctor is not only a surgeon but also did his PhD in liver research.
In the course of his practice, he removes many gallbladders. He states that the formation of gallstones of which cholesterol gallstones are the most common is caused by consumption of carbohydrates.
Chronic carbohydrate consumption creates cholesterol which is created by the liver and settles into the gallbladder as settlement forming gallstones. Gallstones are a byproduct of excessive carbohydrate consumption not fat consumption.
He states that if you have gallbladder issues, then you already have gallbladder disease then your gallbladder hasn’t been working for a long time and yet if you’ve been eating meat you are functioning without the benefit of a gallbladder already. The gallbladder’s purpose is to act as a storage reservoir designed to release bile which helps break down complex fats.
He states that people who have had their gallbladder removed or damaged by gallbladder disease continue to eat fat and they may temporarily experience some digestive issues but that does not preclude a carnivore diet. He states further that there will be pretty close to zero effect on a patient with gallbladder issues or missing gallbladder because the adaptation to functioning without a working gallbladder happened years ago.
The need for a gallbladder surgery is a testament to a long history of carbohydrate addiction and abuse. He in fact recommends a carnivore diet preoperatively to his patients in preparation for gallbladder removal. The reason for this is is that the liver of a carbohydrate addicted person can be six times the size of a normal liver, this is referred to commonly as fatty liver disease. The doctor is an expert in the liver, and he flatly states that a few days on a strict zero carbohydrate or carnivore diet will heal a fatty liver. This shrinks the size of the liver dramatically and firms it up back to its normal state rather than being an gelatinous state which happens with fatty liver making gallbladder surgery extremely difficult, and causing excessive bleeding during the surgery.
He states flat out that gallbladder disease or removal is not a contraindication to eating on a carnivore diet. He says if one encounters difficulty with diarrhea or other gastrointestinal issues eating meats after gallbladder surgery than they should simply back off a bit on their level of fat consumption and slowly increase it as they adapt
This information was taken from a YouTube video posted by Dr. Sean Baker in an interview with Dr. Robert Cywes which can be seen in its entirety here https://youtu.be/Zs4AV4BxNtc
This is not a transcription, but a paraphrase of the discussion as I understand it relies upon the actual video for the most accurate information.