Just a question (I'm not so familiar with the topic): don't ketones strain the liver, because they have to be produced first there (whereas glucose is used directly by the cells)? I'm not sure how demanding the ketone production process is. My guess would be that it's pretty expensive because it's mainly used as a fallback solution, when there's lack of glucose.
I suppose it depends on how you look at it. The liver is always doing something. If you are eating a high carb diet then it is converting lots of glucose into triglycerides for storage. Which is more demanding, creating ketones from fat or triglycerides from glucose? I have no idea.
I also find your assumption that creating ketones is a "fallback solution" implying that it is an abnormal condition, amusing. Based on the catastrophe of our high carbohydrate diets as pushed by our government, (several orders of magnitude increase in, diabetes, auto immune diseases, massive over weight, heart disease, cancer, and all the other modern diseases), what makes you believe that having our bodies run on ketones instead of glucose is abnormal and for emergencies only? Whether our bodies use ketones/fatty acids or glucose as the primary fuel is totally dependent on what you choose to eat. A low carb diet creates a ketone/fatty acid based metabolism, and a moderate to high carb diet creates a glucose based metabolism.
I ate a high carb diet for most of my life as I believed the government and other "health" gurus that carbs and glucose were what our bodies were designed to run on. What I got for my belief system was a 40" waist at 220 lbs (I'm 6'1") for a BMI of 29 which is borderline obesity, high blood pressure 165/95, a fasting blood glucose level of 144, triglycerides of 500+, a cholesterol level of over 250, loss of bone mass with loosening teeth, arthritis in my hands and neck, and severe migraine headaches several times per month that would send me to a dark room in agony for 24 to 48 hours at a stretch.
I've been on a low carb diet with my body running on ketones and fatty acids for about 8 years now. My weight dropped to 160 lbs with a 33 inch waist and a BMI of 21. Blood pressure dropped to 106/65, blood glucose now stays right at 100 fasting or otherwise and seldom varies by more than 10 points either way. Triglycerides have dropped ten fold into the 50's, cholesterol dropped to 180-190 range, arthritis totally disappeared as did my migraine headaches. A DEXA scan and dental x-rays have shown that my bone density has increased significantly as well. My teeth tightened and my average overall bone density has restored to about 95% of that of a 30 year old (I'm 61).
Needless to say, my belief system has changed. I no longer believe that a glucose based metabolism is "normal". My annual blood tests tell the story.
Lex