There are no specific essential carbohydrates (as with the eight/nine amino acids, or the two essential fatty acids), but carbohydrates as a macro-food group are a natural and necessary part of the human diet. The body does store carbohydrates to a limited extent as glycogen, in the muscles and liver.
It is difficult, if not impossible, to get all needed nutrients in a diet devoid of caloric carbohydrates. (Nota Bene: Most fruits contain caloric carbohydrates; avocados are a great exception.)
We do not live in a natural way - in almost any dimension. We do not forage or farm, expending calories. People over-consume caloric (and often nutrient-deficient) carbohydrates, and then sit for hours. Since the body does not burn those calories, they are converted into body fat as stored energy, once the glycogen limit has been exceeded (which is easily done in sedentary individuals).
The Keto Diet is indeed not suitable for continual use: It is too acid-forming systemically (which in the long term promotes numerous degenerative conditions, including especially osteopenia), and too hard on the kidneys and liver. For short term, intermittant, use by persons with healthy kidneys and liver, it can be quite effective.
I nearly died thirty years ago. I studied natural diet and nutrition, and stopped visiting doctors. (I have not consulted with a Medical Doctor since 1995, although if I broke a limb tomorrow, I would immediately do so: trauma, yes, prevention, no.)
My body fat (measured three ways before and after at a college fitness center) went from c. 22% to c. 11%.
(Since I am physically, and legally, disabled, extensive exercise was not an option for me. I had to rely primarily upon diet.)
My current body fat is c. 12-13%, and my waist is 29”. I achieved all of the many benefits through food combining, natural hygeine, herbal cleansing, and nutritional supplementation.
I never once had to resort to the Keto Diet, or its functional equivalent back then, before it became the rage.
I have assisted many over the years, as a I worked as a nutritional consultant in the supplementation industry, and have published one ebook on diet and nutrition, and am writing more. Mine is an informed opinion.
The Keto Diet is indeed not suitable for continual use: It is too acid-forming systemically (which in the long term promotes numerous degenerative conditions, including especially osteopenia), and too hard on the kidneys and liver.
Why didn’t indigenous people around the world (like the Inuit) suffer serious liver and kidney problems from this “acid-forming diet? Were clinical studies done?
Epidemiological studies are worthless when it comes to nutrition.
Did you know that the requirements for nutrients when on a well-formulated ketogenic diet may be very different than those on the SAD diet?
For example, vitamin C competes with glucose - and those in ketosis do not require as much vitamin C as those consuming carbs. Check it out!
Not true at all. Name anything necessary about them.
"It is difficult, if not impossible, to get all needed nutrients in a diet devoid of caloric carbohydrates"
Carbohydrate foods tend to be nutrient poor compared to foods you eat on a ketogenic diet, and there are no necessary nutrients that only come from hi carb foods.
"Since the body does not burn those calories, they are converted into body fat as stored energy..."
It's a more complex process than that. Calories in vs calories out is wrong. That's not how body weight is regulated. Your body and appetite actually adapt to what you are putting in it.
"The Keto Diet is indeed not suitable for continual use: It is too acid-forming systemically..."
Do you mean the high protein diet again? That's not Keto. A ketogenic diet is suitable long term. It is a natural diet for a human. We are carnivores that can consume vegetables when we have to.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2716748/
CONCLUSIONS:
The present study shows the beneficial effects of a long-term ketogenic diet. It significantly reduced the body weight and body mass index of the patients. Furthermore, it decreased the level of triglycerides, LDL cholesterol and blood glucose, and increased the level of HDL cholesterol. Administering a ketogenic diet for a relatively longer period of time did not produce any significant side effects in the patients. Therefore, the present study confirms that it is safe to use a ketogenic diet for a longer period of time than previously demonstrated.