Researchers studied seven people with bipolar disorder who tried a ketogenic diet (a high-fat, low-carb eating plan) for three months. The diet helped with several health markers: it lowered inflammation, reduced belly fat, and improved certain cholesterol levels. However, the diet also raised some concerning markers like homocysteine and advanced glycation end products, which relate to heart and blood vessel health. The results suggest the ketogenic diet might help some people with bipolar disorder feel better and lose weight, but doctors need to carefully monitor individual responses because the effects vary from person to person.

The Quick Take

  • What they studied: Whether a ketogenic diet (eating mostly fats and proteins, very few carbs) could improve heart and metabolic health in people with bipolar disorder who also had unhealthy cholesterol levels
  • Who participated: Seven adults with bipolar disorder who had high cholesterol or other lipid problems, followed for three months while eating a ketogenic diet
  • Key finding: The diet produced both good and concerning changes: good news included 30% lower triglycerides, 45% less inflammation, 12% fat loss, and better HDL cholesterol; concerning changes included 18% higher homocysteine and 106% higher advanced glycation end products
  • What it means for you: If you have bipolar disorder and metabolic problems, a ketogenic diet might help you lose weight and reduce inflammation, but it requires close medical supervision because it can negatively affect certain heart health markers. This is not a one-size-fits-all solution.

The Research Details

This was a case series, meaning researchers followed seven individual patients over three months while they ate a ketogenic diet with a specific fat-to-protein ratio (1.5:1). Before and after the diet period, doctors measured many different health markers related to heart health, inflammation, and body composition. The researchers then calculated the average changes across all seven patients and looked at how much individual responses varied.

The ketogenic diet used in this study was specifically designed as a medical therapy, not just a regular keto diet someone might try on their own. This means it was carefully formulated and monitored by healthcare providers. The researchers measured 15 different health markers, including cholesterol types, inflammation markers, oxidative stress markers (which relate to cellular damage), and body measurements.

This research approach is important because it provides detailed information about what happens to real patients when they try this specific diet. Case series studies are useful for identifying patterns and potential benefits or risks that might warrant larger studies. For people with bipolar disorder who also struggle with weight and metabolic problems, understanding how a ketogenic diet affects their specific health markers is valuable information for making informed decisions with their doctors.

This study has important limitations to understand: it only included seven people, which is a very small group, so results may not apply to everyone. There was no control group (people eating a regular diet for comparison), so we can’t be completely sure the diet caused all the changes. The study lasted only three months, so we don’t know about long-term effects. However, the strength of this study is that it measured many different health markers comprehensively and looked at individual responses, not just averages.

What the Results Show

The ketogenic diet produced several improvements in heart and metabolic health markers. Triglycerides (a type of fat in the blood) dropped by 30% on average. Inflammation markers decreased significantly, with high-sensitivity C-reactive protein dropping 45% and TNF-alpha dropping 7%. Oxidative stress markers also improved: MDA-LDL (damaged cholesterol) fell 38% and nitrotyrosine dropped 28%. Body composition improved with an average weight loss of 4 kg (about 9 pounds), visceral fat (dangerous belly fat) decreased 10%, and total fat mass dropped 12%.

Additionally, lipoprotein(a), a particularly harmful type of cholesterol particle, decreased 21%. The good cholesterol (HDL-C) increased slightly by 5%. Apolipoprotein B, which measures the number of harmful cholesterol particles, dropped 10.5%.

However, the diet also produced some concerning changes. LDL cholesterol (often called “bad” cholesterol) increased 9%, and total cholesterol increased 3%. More concerning were increases in homocysteine (18% higher), which is linked to heart disease risk, and advanced glycation end products (106% higher), which relate to blood vessel damage and aging.

The study noted considerable variation between individuals. While all seven patients showed some improvements in weight and inflammation, their responses to cholesterol changes varied significantly. Some patients’ LDL cholesterol increased more than others, and some showed better improvements in triglycerides. This individual variation is important because it suggests the ketogenic diet doesn’t work the same way for everyone with bipolar disorder.

This research adds to an ongoing scientific debate about ketogenic diets and cholesterol. Some previous studies showed ketogenic diets don’t change cholesterol levels, others showed improvements, and still others showed increases in harmful cholesterol. This case series suggests the answer may be: it depends on the individual. The improvements in inflammation and oxidative stress markers align with other research showing ketogenic diets can reduce inflammation. The concerning increases in homocysteine and advanced glycation end products are less commonly reported and suggest potential risks that need further investigation.

The biggest limitation is the very small sample size of only seven people, making it impossible to know if results would apply to larger populations. Without a comparison group eating a regular diet, we can’t be certain the diet caused all the observed changes—some might have happened anyway. The three-month timeframe is relatively short; we don’t know if these changes continue, reverse, or worsen over years. The study only included people with bipolar disorder and high cholesterol, so results may not apply to people with bipolar disorder without cholesterol problems. Finally, the study didn’t report how well patients stuck to the diet or whether they had any side effects.

The Bottom Line

For people with bipolar disorder and metabolic problems (obesity, high cholesterol, metabolic syndrome): A ketogenic diet may help reduce weight, inflammation, and certain cholesterol problems, but it requires close medical supervision. Before starting, discuss with your doctor whether this diet is appropriate for you. If you try it, get regular blood tests to monitor homocysteine, advanced glycation end products, and cholesterol levels. This is a moderate-confidence recommendation based on a very small study. For people without bipolar disorder: This research doesn’t directly apply to you, though the mixed results on cholesterol suggest caution with ketogenic diets if you have heart disease risk factors.

This research is most relevant for people with bipolar disorder who also have weight problems, high cholesterol, or metabolic syndrome. It may also interest people with bipolar disorder who are looking for dietary approaches to support their mental health and metabolic health together. Healthcare providers treating bipolar disorder should be aware of these findings when discussing diet options with patients. People without bipolar disorder should not assume these results apply to them. Anyone with a history of high homocysteine or heart disease should be especially cautious about ketogenic diets based on these findings.

Based on this three-month study, improvements in weight, inflammation, and some cholesterol markers appeared within the first three months. However, the concerning increases in homocysteine and advanced glycation end products also appeared within three months, suggesting these risks emerge relatively quickly. Realistic expectations: weight loss and inflammation reduction could be noticeable within 4-12 weeks, but you should have blood work done at 4-6 weeks and 12 weeks to monitor for concerning changes in homocysteine and other markers.

Want to Apply This Research?

  • Track weekly weight and waist circumference measurements, and log energy levels and mood daily. Schedule reminders for blood work at 6 weeks and 12 weeks to monitor homocysteine, cholesterol panel, and inflammation markers (CRP). Create a simple daily checklist to track diet adherence to the ketogenic plan.
  • If using a nutrition app, set up the ketogenic diet profile with the specific 1.5:1 fat-to-protein ratio used in this study. Log all meals to ensure you’re hitting the target macronutrient ratios. Set reminders to drink adequate water and take any recommended supplements. Create alerts for scheduled medical appointments and blood work.
  • Establish a baseline of current health markers before starting. Track weight weekly but focus on the trend over 4 weeks rather than daily fluctuations. Log mood and energy levels daily to assess mental health impacts alongside physical changes. Create a simple spreadsheet or app entry to record blood test results at 6 weeks, 12 weeks, and beyond. Compare results to baseline and watch specifically for increases in homocysteine and cholesterol levels. Share all data with your healthcare provider regularly.

This research describes a very small study (seven people) lasting only three months. The findings should not be considered definitive or applicable to all people with bipolar disorder. A ketogenic diet is a significant dietary change that can affect medications, mental health stability, and various health markers. Anyone with bipolar disorder considering a ketogenic diet must discuss this with their psychiatrist and primary care doctor before starting. Regular blood work monitoring is essential, particularly for homocysteine, cholesterol levels, and other markers mentioned in this study. This information is educational and not a substitute for professional medical advice. Individual responses to ketogenic diets vary significantly, and what works for one person may not work for another or could potentially be harmful.