From an evolutionary perspective, the Keto diet isn’t a weight loss diet. It’s a brain health diet.
Keto is a brain health diet because—in times of carbohydrate scarcity (like an arctic winter)—the human brain needs additional fuel. Ketones provide that additional fuel.
Having ketones in circulation (being in ketosis) has multiple brain benefits. It shows promise for treating Alzheimer’s, epilepsy, brain cancer, traumatic brain injury, cognitive decline, and other brain-related conditions.[*][*][*][*]
If this piques your brain’s interest, stick around. This will be a brief tour of Keto benefits for brain health.
How Does Keto Work?
A standard Ketogenic diet is high in fat, moderate in protein, and very low in carbohydrates. In most cases, this means limiting net carbs (total carbs - fiber - sugar alcohols) to between 20 and 50 grams per day.
Why restrict carbs? Because restricting carbs keeps the hormone insulin low, which in turn signals your liver to burn fat.[*] In other words, Keto activates fat-burning mode and suppresses sugar-burning mode.
And in fat-burning mode, you generate brain-fueling molecules called ketones.
Ketones and Your Brain
Picture a hungry hominid in the year 21,208 BC, enduring a harsh winter, surviving on a fatty mammoth carcass. On this (almost) zero-carb diet, our cave-dwelling friend wouldn’t be consuming any glucose, which is typically the “preferred” form of brain fuel.
But in the absence of dietary glucose, their brain wouldn’t shut down. Rather, with glucose scarce, insulin would fall, and they would start making ketones.
Why do humans make ketones? For energy, especially brain energy.
The brain needs a lot of energy. It accounts for 20 to 25 percent of the body’s total energy needs[*], so ketones sure come in handy.
Yet ketones aren’t just any energy source. They fuel the brain differently than glucose.
For example, ketone metabolism generates fewer reactive oxygen species (ROS)—a key driver of oxidative stress and inflammation—than glucose metabolism.[*] In other words, ketones burn cleaner than glucose.
And that’s just the beginning. Ketosis also appears to have therapeutic benefits for a wide range of brain conditions.
Keto for Brain Conditions
Before we review the science on Keto for brain health, a quick note. If you’re considering using Keto to manage a medical condition, always be sure to consult with your medical professional first. With that in mind, let’s dive in.
#1: Neurodegenerative disease
Alzheimer’s disease and Parkinson’s disease are the two most common neurodegenerative diseases. By itself, Alzheimer’s is the sixth leading killer in the US.[*]
Keto may help with both. Consider the following:
- Parkinson’s patients on Keto showed greater improvements in nonmotor symptoms than a low-fat control group.[*]
- Compared to a low-fat group, Alzheimer’s patients on a Keto diet showed increased blood flow to the brain and higher levels of cerebrospinal fluid.[*] (Cerebrospinal fluid is released during sleep and helps clear proteins like amyloid and tau associated with neurodegeneration.)
One explanation for this effect: the aging brain often loses its ability to metabolize glucose, but retains its ability to metabolize ketones.[*] In other words, ketones are a more functional fuel for the aging brain.
In the 1920s, Dr. Russel Wilder of the Mayo Clinic found that a low-carb diet could effectively reduce the duration and frequency of seizures in children with epilepsy.[*] Since then, these findings have been repeated and also expanded to adults.[*][*][*]
Why might Keto help with epilepsy? Possible explanations include:
- The anticonvulsant effects of ketones[*]
- A lack of glucose in the brain “starving” the seizure’s energy supply
- An increase in GABA, a calming neurotransmitter[*]
- A decrease in glutamate, an excitatory neurotransmitter
Again, it’s crucial to work with a physician to create an epilepsy treatment plan.
#3: Brain cancer
Brain cancer can be a frightening diagnosis. The 5-year survival rate is just 36%.[*]
In mice with glioblastoma, a ketogenic diet plus chemotherapy enhanced survival.[*] In humans, several small studies suggest that Keto may slow disease progression of glioblastoma and astrocytoma.[*][*][*]
#4: Traumatic brain injury
When someone suffers a concussion, a cascade of immune cells rushes to the brain to heal the injury. Unfortunately, this response can also damage delicate brain cells.
Keto may attenuate these effects. Most of the evidence is in mice, but it appears safe to now test these findings in humans.[*]
#5: Brain fog
One consequence of brain inflammation is a vague condition called brain fog. Having brain fog means difficulty concentrating, focusing, and thinking. It means not feeling like yourself.
Keto may ameliorate brain fog by:
- Increasing levels of ketones, which are directly taken up by the brain
- Preventing the cognitively-damaging state of high blood sugar[*]
- Decreasing inflammation (ketones have anti-inflammatory effects[*])
#6: Cognitive decline
As we age, certain measures of cognitive performance—working memory, processing speed, executive function—decline.[*] This is true even in people without dementia.
Keto may improve some of these measures. In one study, elderly adults without dementia performed better on a series of cognitive tests while in ketosis.[*]
What about adults with dementia? Keto may improve cognition in that population too.[*]
Who Should Try Keto for Brain Health?
In general, the Keto diet is a safe diet. It’s one of the most researched diets on the planet.
Because of this, Keto has broad relevance for people seeking to improve their brain health. For folks with the aforementioned brain conditions, it’s certainly worth considering.
This consideration should always include the counsel of a medical professional. (If possible, a medical professional familiar with Keto’s therapeutic applications.)
Without proper supervision, an underweight child with epilepsy could lose weight on Keto. And that could be dangerous.
The lesson is simple. Whether you're using Keto for brain health, weight loss, or another benefit, careful planning and consideration are the keys to success.