Keto has become one of the most popular – if not misunderstood – concepts in modern health.
First described in the 1900s as a therapeutic diet for children suffering from epileptic seizures, keto is now used to eliminate sugar and carbohydrates from the standard American diet, helping with such things as weight loss and diabetes control.
The standard American diet is very heavy in carbohydrates, and focuses the body on sugar for a consistent supply of energy. Keto, on the other hand, switches to burning fat as a long term source of energy by using ketone bodies – thus the name ‘ketogenic’ diet. A ketogenic diet encourages health by lowering the consumption of sugar, glucose, or carbohydrates (breads, sweets, pastas, and similar staples).
Keto’s overwhelming popularity has created several questions about its effects on the body, including long term metabolic health. It can be difficult to get straight answers from conflicting sources of information.
As a heart surgeon, I answer questions all the time about the efficacy of ketosis. Let’s answer some popular myths about ketogenic diets and how they came to be.
Is long-term ketosis unhealthy?
Evidence suggests that humans have been in a state of ketosis for most of our history. Ancient man may have come out of ketosis for brief amounts of time, but limited access to sugar would not have allowed for consistent glucose burning.
Anecdotally, I know several people who have stayed on keto for years without trouble. But beyond that, look at the root of ketogenic diets. Controlling seizures is a long term and lifelong process, not a fad diet.
The evidence is all around us that people can sustain ketogenic diets for long periods of time.
Will being in ketosis cause diabetic ketoacidosis (DKA)?
Diabetic ketoacidosis is a unique philological event that happens to diabetics when their blood sugar gets very high. Ketones in the blood cannot be broken down, leaving the patient in an acidic state.
DKA is a very different diagnosis from entering a state of ketosis. In fact, this common misconception stems from similar sounding words, and not from similar effects or prognoses.
If you are planning on trying a ketogenic diet, diabetic ketoacidosis will not be a concern for you at all.
Does being in ketosis cause hypoglycemia?
It’s true that the body has less need for glucose while in a state of ketosis. However, this rarely gives rise to dangerously low blood sugar levels.
When I am in deep ketosis, my blood sugar will run at exceedingly low levels but I don’t experience any of the symptoms that typically accompany hypoglycemia. My body no longer needs an excess of glucose in the blood, and will allow my blood sugar to get lower than it normally would. Energy consumption switches to ketones, which is a more sustainable source of power.
Having low blood sugar can be very problematic if you aren’t in a state of ketosis. But lower blood sugar levels associated with ketogenic diets is not necessarily a bad thing. This is one of the reasons why keto makes such great therapy for those with diabetes.
If you are a diabetic and considering a keto diet, please speak with your primary medical doctor. Certain types of medication or exercise may put you at a greater risk for blood sugar complications, although there are several approaches that mitigate risk. I personally know type 1 and type 2 diabetics who have been quite successful with a ketogenic strategy.
Is the brain damaged by being in ketosis?
The human brain does not experience damage from remaining in a ketogenic state. In fact, one of the first things that people describe on a keto diet is a sharper mental state. The myth here is that the brain requires high levels of glucose to function well, but the science suggests that the opposite is true.
The human brain is an organ capable of running on glucose or ketones. While in keto, your brain runs off ketones, which is a highly efficient form of energy. Ketones provide more energy per oxygen unit used, which is more advantageous to the brain.
Millions of people have benefitted from ketogenic diets, all without ever running into issues related to brain damage or loss of function.
Does ketosis damage heart or vascular function?
In all my years as a heart surgeon, I have never seen evidence that ketosis damages cardiac function. In fact, there’s some evidence that keto may actually be beneficial to the heart. People experiencing heart failure have successfully used ketosis to improve their heart function, as cited in multiple research studies.
This is related to another popular myth that high-fat ketogenic diets lead to heart disease, specifically from saturated fat in animal-based proteins that increase cholesterol. This idea was explored in depth by Ancel Keys, who purported that increased consumption of dietary fat leads would lead to the development of plaque within the arteries of the heart.
This hypothesis has never been proven. The relationship between dietary levels of fat and cholesterol in the bloodstream is inconsistent at best. The relationship between elevated cholesterol and heart disease remains suspect as well.
I believe that elevated blood cholesterol levels are only harmful in the presence of damage to the blood vessel walls and oxidized cholesterol particles. Without inflammation and in a non-oxidized environment, there is no evidence of LDL cholesterol harm to the heart or vascular function.
In short, there is no correlation between rampant heart disease and those who follow a ketogenic diet.
Are keto foods bad for your heart?
The term ‘ketogenic diet’ used in the medical field is very different from the ‘keto’ diet talked about in popular culture.
Popularized by weight loss gurus, keto has taken the food industry by storm. Thousands of products tenuously labeled ‘keto’ have filled up the shelves. As an unregulated term like ‘organic’ or ‘fresh,’ companies can print the words ‘keto’ on anything with little to no consequence. Worse, some food companies create junk processed food in a ‘keto’ way by substituting real foods with man-made synthetics.
You need to be careful about consuming processed keto products that are no better than full sugar alternatives. I suggest constructing a ketogenic diet that includes whole, real food. Don’t fall for a diet filled with processed foods and unhealthy alternative sugars.
Learn More About Keto Diets
If you want to learn more about keto diets and how they can help to improve your metabolic health, I suggest reading the work of certified medical professionals. My book Stay Off My Operating Table provides a metabolic health guide that discusses tenants of healthy eating, disease prevention, and a sustainable diet shift.