Chronic ketosis can lead to the detrimental oxidation of polyunsaturated fatty acids.

“you can burn fat while you're eating carbohydrates that if you're in a ketogenic diet or you're limiting carbohydrates people say you're burning fat well you're burning the fat that you're eating you're not necessarily burning the fat on your body and even if you're doing lipolysis and burning the fat on your body that's a process that is often going to lead to the lipolysis of the oxidation of polyunsaturated fatty acids which is not a good thing is to actually be in a chronic ketosis”