The idea that what we eat can influence how we feel is nothing new, but the idea that something adopting a lifestyle change to a keto diet can help people with serious mental health issues like bipolar disorder or schizophrenia is a relatively new idea. Most of us know following a nutritious diet plan can promote physical strength and improved mood, while regularly consuming junk food can have the opposite effect.
But can food actually have an impact on the symptoms of complex mental health concerns?
Several recently published studies suggest that it can.
These studies investigated the influence of a ketogenic diet, a.k.a. the keto diet, and they determined that this high-fat, low-carb plan can offer physical and psychological benefits to people who have a variety of mental illnesses, including bipolar disorder and schizophrenia.
Shebani Sethi, MD, describes her team’s research in press release from Stanford Medicine:
“It’s very promising and very encouraging that you can take back control of your illness in some way, aside from the usual standard of care.’
What Is the Keto Diet?
The ketogenic (keto) diet has received considerable attention over the past few years, primarily due to its potential weight loss benefits. According to the International Food Information Council, the number of Americans who followed the keto diet grew from 10 million in 2018 to more than 20 million in 2022.
Though it has enjoyed a recent surge in popularity, the keto diet is not new. For example, The Atkins Diet, which was introduced in the 1970s, now bills itself as “the original low-carb keto diet.”
But the history of this diet goes back further. As described in a 2008 article in the journal Epilepsia, Dr. Russell Wilder of the Mayo Clinic introduced the keto diet in the 1920s as a treatment for epilepsy.
According to the University of Kansas Medical Center, the original keto diet plan advised that a person’s daily caloric intake should come from the following sources:
- 70%-75% from fat
- 20%-25% from protein
- 5%-10% from carbohydrates
What does this look like in terms of the actual foods a person eats? Here’s a quick overview:
- A keto diet is in seafood, meat, poultry, and dairy products, as well as certain high-fat vegetables and other low-carb foods.
- Breads, pasta, potatoes, sugared beverages, and some beans or legumes are off-limits by keto adherents.
When someone follows this plan, their limited carb intake forces their body to burn stored fat as an energy source. Medical experts refer to this as a state of ketosis, which is the source of the term ketogenic.
The ketogenic diet promotes a consistent insulin level, which is beneficial for people who have diabetes. Burning stored fat can lead to weight loss, which explains the longstanding popularity of the approach.
If further studies confirm the mental health outcomes we mention above, the advantages of the keto diet may not be limited to weight loss and insulin control, but may show that a keto diet can help people with bipolar disorder and schizophrenia.
Mental Health Benefits of the Keto Diet
In January 2023, the Journal of Affective Disorders Reports published a review of prior research on the potential of the keto diet as a form of metabolic therapy for people with bipolar disorder.
Highlights of this review:
- Evidence suggests metabolic dysfunction may be a root cause of bipolar I disorder, bipolar II disorder, and cyclothymia.
- The effects of a low-carb ketogenic diet mimic the mechanisms of some mood stabilizing medications.
- Beneficial effects of the keto diet may include repairing or bypassing metabolism deficits, decreasing inflammation, and regulating mood.
- Alternative energy that the body produces while in a state of ketosis may offer neuroprotective benefits and other favorable outcomes.
The January 2023 review also cited a July 2022 retrospective analysis from the journal Frontiers in Psychiatry. That analysis looked at the effect of the ketogenic diet on a small group of patients who had severe, persistent, and poorly controlled symptoms of three mental illnesses:
- Bipolar II disorder
- Major depressive disorder
- Schizoaffective disorder
All participants in this analysis also exhibited at least one sign of poor metabolic health, such as obesity, hypertension (high blood pressure), or elevated fasting blood glucose.
For this analysis, 28 patients followed a ketogenic diet for at least two weeks. The results of this effort included:
- All 10 patients who had schizoaffective disorder showed improvement as scored on the Positive and Negative Syndrome Scale (PANSS). The mean PANSS score decreased from 91.4 to 49.3 over the course of the study.
- Among the 23 patients who took the Hamilton Depression Rating Scale (HAM-D), the mean score fell from 25.4 to 7.7. Twenty-one of these patients achieved a drop of seven or more points, which the authors identified as the threshold for “substantially clinically important” improvement.
- The researchers evaluated the severity of 27 patients’ illnesses with the Clinical Global Impressions Scale (CGI-S). All 27 improved by at least two points.
Here’s how the researchers describe these results:
“Given that the interventions implemented during this hospitalization differed only in the addition of the [ketogenic diet] to usual care, we believe it is likely that the [ketogenic diet contributed considerably to these unprecedented mental health improvements.”
Impact on Bipolar Disorder and Schizophrenia
The Stanford University research team we mention in the introduction recently conducted a four-month pilot study to the impact of the keto diet on people with bipolar disorder and schizophrenia.
This study, which appeared in the May 2024 edition of Psychiatry Research, included 21 participants who met the following criteria:
- Diagnosed with bipolar disorder (16 participants) or schizophrenia (5 participants)
- Taking antipsychotic medications
- Have experienced insulin resistance, impaired glucose tolerance, hypertriglyceridemia or another metabolic abnormality
Features of the study:
- Participants followed a keto diet of 60% fat, 30% protein, and 10% carbohydrates and met with a physician 10 times during the study period.
- Participants received psychiatric assessments at baseline, at the midpoint of the study (two months after baseline), and at their final visit (four months after baseline).
- Assessments included participant-reported standardized questionnaires and clinical assessments with a psychiatrist.
- Participants had access to health coaches for advice on food choices and to promote adherence to the keto diet.
Results:
- Overall symptom severity: 31% improvement
- Participants who reported full adherence to the diet: 92% showed improvement
- Participants who reported partial adherence: 50% showed improvement
- Among participants with bipolar disorder with full adherence: 88% showed improvement
- Among participants with bipolar disorder with partial adherence: 60% showed improvement
- Participants with schizophrenia: 32% reduction in symptoms
In addition to these mental health benefits, participants also achieved an array of physical health gains, including:
- Metabolic syndrome: 100% decrease
- Weight loss: 10% of body weight on average
- Average weight circumference decrease: 11%.
- Average systolic blood pressure reduction: 6.4%.
Here’s more commentary from Dr. Sethi:
“The participants reported improvements in their energy, sleep, mood, and quality of life. They feel healthier and more hopeful.”
Why Does the Keto Diet Improve Symptoms of Bipolar Disorder and Schizophrenia?
The researchers investigated the ability of the keto diet to help patients achieve improved mental health, but they didn’t try to determine why this diet change produced these results. However, alone with other experts, they have theories, such as:
- When the brain draws energy from ketones instead of glucose, it may improve efficiency.
- A ketogenic diet may reduce inflammation in the central nervous system while increasing the level of GABA, a mood-regulating neurotransmitter.
- The state of ketosis may improve the functioning of mitochondria, the cells that produce adenosine triphosphate (ATP), our primary energy source.
- Ketosis may also decrease the impact of oxidative stress, a natural process that damages cells and tissues.
Dr. Sethi told the Washington Post:
“The working theory is that we’re providing energy to the brain that circumvents … metabolic deficits.”
What Happens Next?
While research on the ketogenic diet and mental health has been mostly positive, much work remains to ascertain the degree and durability of keto-inspired improvements, and how the keto diet may help people with bipolar disorder and/or schizophrenia.
Most previously published studies were relatively small, and several lacked a control group. Also, researchers have yet to evaluate either long-term side effects or the likelihood that patients will follow the keto diet for an extended period.
In an email to the Washington Post, nutritional psychiatrist Drew Ramsey, MD, offered this insight:
“The big questions around keto and patients with severe mental illness are around compliance, sustainability, and potential negative metabolic effects.”
Conclusion: Can a Keto Diet Help Me if I Have Bipolar Disorder or Schizophrenia?
The answer: a solid maybe.
If you have a complex mental illness and you believe the ketogenic diet may be helpful, please don’t make any dietary changes until you consult with your physician, psychiatrist, and any other professional physical or mental health providers you see.
Significant changes in eating habits can have dramatic – and often unintended – consequences. Your treatment team can assess the potential physical and psychological effects the keto diet or any other change may have on you. If they approve any diet modifications, they can also help you implement the changes safely and monitor your progress.
Gianna Melendez
Jodie Dahl, CpHT