By Dr. Stephen Phinney and the Virta Team
Butter, cheese, cream, and Greek yogurt are excellent sources of protein, fat and calcium; and there is no need for people to avoid them unless they have specific symptoms brought on by their consumption (e.g., lactose intolerance). That said, avoid high-carb dairy products such as milk (full fat, 2%, and skim) because they contain enough carbohydrate (as lactose) to drive down blood ketone levels.
Followers of the Paleo diet avoid dairy products on the grounds that our distant ancestors did not consume them. But since many people following a well-formulated ketogenic diet tolerate reduced lactose dairy and benefit from its protein, fat and calcium contents, there is no need to exclude it unless you specifically choose the Paleo approach to low carb.
See our blog post ‘Paleo vs Keto – What’s the Difference?’