Is it possible to overindulge on fats during keto?

Ive recently discovered how satisfying throwing a tablespoon of mayo on 3 eggs can be. And lately, Ive been eating at Mcdonalds and throwing out the bun/condiments and just eatting the fatty meat and cheese. But surely theres a limit to how much fat you can eat before your body just gives up and gets fat again, right? Is this when calorific deficit/surplus comes into play?
 
Keto has worked wonders for me, but I am aware that if i stuck to only healthy fats, it would be an incredibly difficult diet for me. Its cheese, mayo, and greasy meat thats been doing it for me and Ive still been losing, but Im still concerned.

If your goal is just general weight loss- Stick to what works.

If your goal is healthy weight loss- Avoid McDonalds, the stuff in that just isn't good for your body's heart and arteries in general.

I'd stick with regular veggies and proteins if I were you.

ACE-CPT, NASM-CPT, AFPA-Nutrition Consultant 

I don't know what's in the McDonalds burger meat and such products. But a lot of cheap burger and sausage meats are actually high in carbs, sometimes even higher than that of the protein or fat content. Just a heads up :)

Try to limit the fats from meat products when you can and focus on nuts, nut butters, EVOO, fish and avacados.  Some people really like the other oils as well, like coconut.