Dad judging my family because of his diet..

My dad has become obsessed with the keto/carnivore diet. He had a health scare a few years ago and has been going down the YouTube health influencer hole ever since. It’s gotten to the point where he is even more unlikeable than before (he was never an overly friendly/warm person). My family eats healthy but we also eat starches like potatoes, and fruits and veggies. My dad can’t contain himself most of the time and has to make an underhanded comment about how disgusting and horrible it is and how it’s poison and im giving my kids drugs basically. He has a super strict diet and only eats one time per day (4 pm on the dot). It’s basically animal organs and a small handful of blueberries and washes it down with vinegar water. Thats ALL he eats. He aggressively pushes it on my mom too. When she visits my house alone, she raids my fridge desperately looking for crackers or fruits. It’s gotten to the point where I don’t want to invite him over any more. He will scan my counters looking for “poison” so he could hatefully fume about it for the next week until he cant bottle it in and tell me about it. My wife is getting annoyed with him too and feels insulted as a mother when he makes these comments. He sounds very self righeous and judgemental. None of us are overweight or have health issues. Yes we like to indulge in sweets occasionally and yes I’ll make my kids Mac n cheese when we have to make something quick! My dad could be more happy that I’ve given him 5 beautiful grand kids but instead he only focuses on the negatives like our diet.