Enthusiasts deem the ketogenic diet a cure-all, but the low-carbohydrate and high-fat food plan isn’t as beneficial for diabetes or weight-loss as keto-worshippers claim. In fact, this fad diet actually carries the potential for serious side effects including heart disease, kidney stones, high cholesterol, keto flu, selenium deficiency, cardiac arrhythmias, and even death. Given the lack of real health benefits and the potential for serious damage, as a medical doctor, I caution people before they hop on the keto diet train. My VegNews.com article, “8 Reasons to Forget Keto and Go Vegan,” detailed why a whole foods, plant-based diet is the healthier path to take, but some keto fans weren’t convinced. I now present 8 more medical reasons to avoid the keto diet and go vegan instead.


1. The Inuit are not in ketosis for a good reason
Despite popular misconception, the Inuit are not in ketosis, largely due to a widely-prevalent genetic mutation in the Arctic Inuit that prevents its occurrence. Although this may seem like fun trivia, it actually has sinister undertones. Ketosis was likely detrimental to the Inuit over generations and favored the survival of those with the mutation that circumvented the production of ketone bodies. One theory for this is that ketoacidosis—a potentially fatal complication—occurred too easily during times of stress, like illness, injury, or complete starvation. The combination of the keto diet and stress lowered the body’s pH to the point of ketoacidosis, causing the blood to be too acidic and resulting in death.

2. Vitamin and mineral deficiencies galore
The keto diet has a long history of being used as treatment for children with refractory epilepsy. In one study, researchers found those young people had deficiencies in their levels of thiamin, riboflavin, niacin, pantothenic acid, vitamin B6, folate, biotin, vitamin C, calcium, phosphorus, magnesium, iron, zinc, copper, selenium, manganese, chromium, and molybdenum. Worse, the degree of deficiency usually increased with more ketosis, likely a result of increasingly restrictive diets.

3. Stunted growth
Also according to pediatric epilepsy literature, researchers noted another common side effect among children on the ketogenic diet: stunted growth. Children on the diet were not growing as fast as their peers on carbohydrate-rich diets. One reason for this is that they were found to be deficient in many important minerals essential for bone growth, like calcium, phosphorus, and vitamin D.

4. No benefit to glucose levels
Keto enthusiasts claim the diet can lower glucose levels, which makes sense since it severely restricts carbohydrates. However, in a meta-analysis comparing low-carbohydrate ketogenic diets to low-fat diets, researchers analyzed eight studies of 770 participants and found no difference in fasting blood glucose levels between the two groups after one year of being on the diets. One possible explanation is that despite the reduced carbohydrate consumption, glucose metabolism worsened with the higher fat consumption on the ketogenic diet.

5. Pancreatitis
Within the pediatric epilepsy literature, there are several documented instances of pancreatitis while on the ketogenic diet, with at least one of them being fatal. Nobody fully understands why the ketogenic diet may cause pancreatitis, but it is suspected to be from the high-fat content of the diet, leading to higher levels of cholesterol and triglycerides in the blood. Extremely high levels of triglycerides in the blood are a known cause of pancreatitis.

6. Gastrointestinal rumblings
The ketogenic diet has been known to cause numerous gastrointestinal problems besides pancreatitis. This is in no small part from the lack of fiber, which, as one would expect, causes constipation. Fiber is important for the number and size of bowel movements and is only found in plant-based foods. Keto dieters eat non-starchy vegetables and get some fiber, but eating too much will pull them out of ketosis, limiting their fiber intake. Other common gut issues include nausea and vomiting, along with other side effects in the unpleasant phenomenon dubbed the “keto flu.”

7. Birth defects
There is emerging evidence that low-carbohydrate diets like the ketogenic diet could be dangerous to unborn babies. In one study, researchers found that mothers who were on a low-carbohydrate diet had a 30 percent higher risk of having a baby with spinal cord problems or without a complete brain.

8. Broken Bones
With so many deficiencies in the nutrients important to healthy bones, like calcium and vitamin D, it is not surprising that bone health decreased in many children on the ketogenic diet. Some children had a decline in bone mass while others had overt skeletal fractures. Another reason for the poor bone health may be the chronic metabolic acidosis seen in ketogenic diets, which could weaken bones over time as the body uses alkali from bones to buffer the acid in blood.

With an ever-expanding list of reasons to skip the diet, I am hard-pressed to find a good reason to go on the diet, especially when it risks developing any number of health problems. People who are looking to lose weight or reverse their diabetes or any other lifestyle disease should consider a healthy vegan diet that is rich in whole-foods, like fruit, vegetables, whole grains, nuts, and legumes. In the end, the best diet for humans is one that uses whole-foods from plant-based sources, which, of course, does not carry all the problems seen with the ketogenic diet.

Shivam Joshi is a nephrologist, internist, and lifestyle medicine physician practicing at an academic medical center in New York City.

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