Butter

I am starting my journey next week and just trying to plan my next grocery order. I see boiled eggs mentioned often and since I have chickens, that's an easy item for me. Also, I love boiled eggs BUT only with a pat of butter and some black pepper. I've been unable to find any info in the forum about butter, when I attempt to search I find only peanut butter. Can anyone tell me if adding butter to eggs or potatoes has had a bad effect for you? Thanks in advance.