Thought to boost brain health and cognitive abilities, the keto diet is being adopted by those looking to stay mentally sharp in the professional world. Let’s examine the evidence.
The ketogenic diet, or the “keto diet” as some call it, is sweeping across the country and is purported to be a panacea for all that ails the human race. It’s especially being promoted as an strategy for weight loss and fat-burning, but there is another reason that a certain subset of professionally-driven individuals in high-demanding industries are flocking towards the keto diet:
Mental clarity and cognitive performance.
Many Silicon Valley workers and those in similar high-paced professional industries, say they have started keto because they want to live longer and most interestingly, sharpen their minds. While there is some research evidence to support the positive cognitive effects of following a ketogenic diet in elderly individuals already experiencing cognitive decline, the question remains: Is this research substantial enough to conclude that following such a diet will lead to cognitive improvement in healthy individuals? Let’s take a closer look.
But first, a quick primer on what the keto diet is.
The standard and most often prescribed ketogenic diet is a very high-fat, extremely low-carbohydrate diet that has been shown to help to control seizures in some people with epilepsy, especially children. A person’s overall daily carbohydrate intake when following this diet is around 30 grams, making it more restrictive than both the Atkins and Paleo type diets.
To give you a visual, 30 grams of carbohydrates is the equivalent to a heaping bowl of strawberries, one banana or two slices of bread. It’s not nearly enough to sustain an adult human. In fact, ketosis is an evolutionary survival mechanism that allows a human body to use ketone bodies during times when it does not have access to adequate carbohydrates, the preferred fuel source for the body and brain. There is a shift from the use of glucose as fuel to the use of fatty acids and ketones as fuel, hence the name “the ketogenic diet”.
Now, let’s take a look at some of the research in support of using the keto diet to improve cognitive function.
One study using 23 older adults with mild cognitive impairment measured cognitive improvements under ketosis by splitting group participants into two groups (high carbohydrate diet or very low carbohydrate diet). The study found that ketone levels were positively correlated with memory performance.
In another study, 152 older adults with mild to moderate Alzheimer’s disease were given either ketone injections or a placebo, while maintaining a normal diet. It showed that those receiving treatment showed improved cognitive function compared to placebo, which was correlated with the level of ketones in the blood.
Results of studies like this have led normal, healthy humans to believe they can stave off neurodegeneration, cognitive decline and protect themselves from Alzheimer’s, which scientists are still hard at working trying to understand and resolve. While there may be some cognitive improvements shown in short-term research studies, it’s important to keep in mind these studies have been largely based on individuals with a specific health concern or in the elderly population.
In fact, studies often state that the keto diet is not efficacious in regards to significant cognitive improvements, and that more research needs to be done before we can make such conclusions. For example, in one year-long randomized controlled study, they found no significant difference in cognitive functioning when measuring working memory and speed of processing between those on a low-carb, high-fat vs. participants on a high-carb, low-fat diet.
In another study that evaluated the cognitive skills of low-carb dieters in comparison to reduced calorie diets, dieters who eliminated carbohydrates from their meals actually performed more poorly on memory-based tasks. In addition, a review of 15 studies looking at the role of the keto diet in mental health concluded its efficacy is unclear. Half of the published studies related to mental health are based on animal models of mental disorders, making it hard to extrapolate this information and apply it to humans.
Thus, for otherwise healthy individuals, there is currently little evidence that following a keto diet will improve cognitive function or mental health in the long run.
It cannot be dismissed, that for some individuals, the keto diet may make them feel mentally sharper and more energetic, which may be due to genetic adaptation or their own positive perceived benefits. However, for the majority of folks, jumping into such a strict diet might actually leave them worse off psychologically.
Such dieting and restriction of carbohydrates can and will often lead to intense cravings due to the body’s need to have adequate carbohydrates on board to function most optimally and meet its needs. This ultimately can lead to episodes of overeating or binging on carbohydrates, which is a normal response to deprivation. Sometimes, it can feel so intense that some may report feeling “out of control.”
This often leads to individuals blaming themselves for “not having enough control”, and for not trying hard enough.
Restricting foods (dieting) can lead to an increased desirability of those same “forbidden foods”, can increase food preoccupation or time spent thinking about food, and can contribute to eating in the absence of hunger. Restriction has also been shown to increase taste and reward stimulation, which means that when dieters deprive themselves of a particular food or food group, they experience an increased reward and pleasure from forbidden foods in comparison to non-dieters.
Studies also often don’t address a key piece: acknowledging how low-carb diets can negatively affect mood due to changes in the brain’s production of serotonin. The evidence showing the link between the brain’s serotonin production and its connection to depression and anxiety is clear, but what is not being discussed is how low carbohydrate diets remove foods that contain tryptophan, the precursor to serotonin, which may affect one’s mood state.
And let’s not forget the other acute adverse symptoms, including kidney stones, constipation due to low overall fiber intake, headache, muscle cramps from micronutrient deficiencies, diarrhea and weakness, and excessive protein intake that leads to the infamous “keto-breath”.
So much for being ‘healthy’.
There’s no doubt that the regimented nature of the ketogenic diet may be appealing for individuals who operate in a similar manner in their professional life. Having rigid control over the diet, and the perceived notion of having control over the outcome of disease development, can add to the appeal.
Finding more work-life balance and creating peace with food, however, may be a more sustainable option in the long term.
HEADER IMAGE: ANNIE SPRATT
Katherine Metzelaar, MSN, RDN, CD is a Seattle-based registered dietitian and nutrition therapist who helps individuals repair their relationship with food free from perfectionism, fear, and shame. She works with clients to create more flexibility and freedom with food, giving them the tools to decrease their fear of food. Learn more about Katherine at Bravespace Nutrition.