A ketogenic diet is comprised of approximately 10% of daily calories coming from healthy carbohydrates such as leafy greens, nonstarchy vegetables, and limited amounts of legumes and berries; 20% of daily calories coming from proteins such as omega-3-rich fish and grass-fed animal protein; and ~70% of daily calories coming from high-quality fats such as avocado, unsaturated and medium-chain triglyceride oils, nuts and seeds, and coconut.
Even hibernating bears do not go into ketosis. And predatory animals who undergo extended periods of food deprivation, such as elephant seals, are metabolically resistant to ketosis; instead, they have upregulated gluconeogenesis pathways through which they can steadily produce glucose. This makes perfect sense, since predators’ survival depends on their ability to catch their prey, which usually requires intense bursts of activity. And sprinting capacity is dependent on glucose, as humans who adopt a ketogenic diet quickly discover.
The ketogenic diet has been studied in at least 14 rodent animal models of seizures. It is protective in many of these models and has a different protection profile than any known anticonvulsant. Conversely, fenofibrate, not used clinically as an antiepileptic, exhibits experimental anticonvulsant properties in adult rats comparable to the ketogenic diet. This, together with studies showing its efficacy in patients who have failed to achieve seizure control on half a dozen drugs, suggests a unique mechanism of action.
As in adults, glucose is the predominant cerebral fuel for the fetus and newborn. Studies in experimental animals and humans indicate that cerebral glucose utilization initially is low and increases with maturation with increasing regional heterogeneity. The increases in cerebral glucose utilization with advancing age occur as a consequence of increasing functional activity and cerebral energy demands… glucose plays a critical role in the developing brain, not only as the primary substrate for energy production but also to allow for normal biosynthetic processes to proceed.
Another difference between older and newer studies is that the type of patients treated with the ketogenic diet has changed over time. When first developed and used, the ketogenic diet was not a treatment of last resort; in contrast, the children in modern studies have already tried and failed a number of anticonvulsant drugs, so may be assumed to have more difficult-to-treat epilepsy. Early and modern studies also differ because the treatment protocol has changed. In older protocols, the diet was initiated with a prolonged fast, designed to lose 5–10% body weight, and heavily restricted the calorie intake. Concerns over child health and growth led to a relaxation of the diet's restrictions. Fluid restriction was once a feature of the diet, but this led to increased risk of constipation and kidney stones, and is no longer considered beneficial.
Con: Results can vary depending on how much fluid you drink. By drinking more water, you dilute the concentration of ketones in the urine and thus a lower level of ketones will be detected on the strips. The strips don’t show a precise ketone level. Finally, and most importantly, as you become increasingly keto-adapted and your body reabsorbs ketones from the urine, urine strips may become unreliable, even if you’re in ketosis.
I have great respect for Harvard Medical School. I notice that they support their readers posting comments and I am most appreciative of the article and all the many thoughtful comments by the readers. The readers seem to have the most expertise here and I hope that the doctor who wrote the article will think long and hard about the comments by readers. After 35 years of clinical practice in mental health, I notice that all issues of emotion involve medical issues, nutrition, and the gut bacteria. I would say that these issues and all of the executive brain functions seem to improve with ketogenic principles. For those that apply it in a flexible and smart manner, it appears to improve every area of their lives. I strongly encourage the author of the article to take one class via The Institute for Functional Medicine. If he is open to more learning he can take more classes and get certified. I’m sure a fine doctor, he will be an even better doctor and personally healthier, if he gets more training. Are we all open to new learning(especially us healthcare providers)?
Sleep enough – for most people at least seven hours per night on average – and keep stress under control. Sleep deprivation and stress hormones raise blood sugar levels, slowing ketosis and weight loss a bit. Plus they might make it harder to stick to a keto diet, and resist temptations. So while handling sleep and stress will not get you into ketosis on it’s own, it’s still worth thinking about.