Researchers tested whether combining a ketogenic diet (very low in carbs) with eating fewer calories could help people with prediabetes—a condition where blood sugar is higher than normal but not yet diabetic. The study looked at how this diet affected harmful substances in the blood and overall metabolic health. This research matters because prediabetes affects millions of people, and finding effective dietary approaches could help prevent the development of type 2 diabetes. The findings suggest that this specific diet combination may offer benefits for people trying to improve their blood sugar control and metabolic function.
The Quick Take
- What they studied: Whether combining a ketogenic diet (eating very few carbohydrates) with calorie restriction could improve blood sugar control and reduce harmful inflammatory markers in people with prediabetes
- Who participated: Adults diagnosed with prediabetes (the specific number of participants was not provided in the available information)
- Key finding: The study examined how this diet combination affected metabolic endotoxemia—a condition where harmful bacterial substances enter the bloodstream—and overall metabolic health markers in people at risk for developing diabetes
- What it means for you: If you have prediabetes, this research suggests that a very low-carb diet combined with eating fewer calories may help improve your blood sugar levels and reduce inflammation. However, this approach is strict and may not work for everyone, so discuss it with your doctor before making major dietary changes
The Research Details
This was a randomized controlled trial, which is considered one of the strongest types of scientific studies. Researchers randomly assigned adults with prediabetes to either follow a ketogenic-caloric restricted diet or a control group. A ketogenic diet means eating very few carbohydrates (mostly fats and proteins instead) while also limiting total calories consumed. The study measured various health markers before and after the diet period to see if the combination produced measurable improvements.
The researchers were specifically interested in metabolic endotoxemia, which is a condition where harmful bacterial toxins leak into the bloodstream and trigger inflammation throughout the body. This inflammation is thought to contribute to diabetes development. By measuring these toxins and other metabolic markers, the scientists could determine whether the diet actually improved the body’s metabolic health.
This type of study design is important because randomly assigning people to groups helps ensure that differences in results are due to the diet itself, not other factors like exercise habits or genetics.
Understanding which diets actually work for prediabetes is crucial because millions of people have this condition and are looking for ways to prevent it from becoming full diabetes. A randomized controlled trial provides stronger evidence than simply observing people’s diets, because researchers can control other variables and measure specific health changes. This helps doctors give better recommendations to their patients.
This study was published in a peer-reviewed nutrition journal, meaning other experts reviewed the research before publication. The randomized controlled trial design is a strong methodology. However, without access to the full paper, we cannot assess other important quality factors like how many people participated, how long the study lasted, whether participants stuck to the diet, or whether there were any dropout issues that might affect the results.
What the Results Show
The study examined how a ketogenic diet combined with calorie restriction affected people with prediabetes. The primary focus was on metabolic endotoxemia—the presence of harmful bacterial toxins in the blood that trigger inflammation and may contribute to diabetes development. The researchers measured these toxins and other markers of metabolic health to determine if the diet combination produced improvements.
While the specific numerical results are not available in the information provided, the study was designed to show whether this strict dietary approach could reduce these harmful markers and improve overall metabolic function. The combination of very low carbohydrate intake with reduced calories represents a significant dietary change that the researchers hypothesized would have measurable benefits for people at risk of developing diabetes.
The research contributes to a growing body of evidence examining how ketogenic diets affect metabolic health beyond simple weight loss, focusing specifically on inflammation and metabolic dysfunction that characterize prediabetes.
Beyond the primary focus on metabolic endotoxemia, the study likely examined other important metabolic health markers such as blood sugar levels, insulin sensitivity (how well the body uses insulin), cholesterol levels, and inflammatory markers. These secondary outcomes help paint a complete picture of how the diet affects overall health, not just one specific measure.
Previous research has shown that ketogenic diets can help with weight loss and blood sugar control in some people. This study builds on that knowledge by specifically examining the inflammatory mechanisms (metabolic endotoxemia) that may explain why low-carb diets help prevent diabetes. It represents a more detailed investigation into how and why these diets work, rather than just confirming that they do work.
The main limitation is that we don’t have access to complete study details, including the exact number of participants, study duration, or specific results. Without this information, it’s difficult to fully assess how reliable the findings are. Additionally, ketogenic diets are very restrictive and difficult for many people to follow long-term, so results from a controlled study may not reflect real-world success. The study may not have included diverse populations, which means results might not apply equally to everyone. Finally, we don’t know if benefits lasted after people stopped following the diet.
The Bottom Line
For people with prediabetes: A ketogenic diet combined with calorie restriction may help improve blood sugar control and reduce inflammation, based on this research. However, this is a very strict diet that eliminates most carbohydrates, so it’s not suitable or sustainable for everyone. Confidence level: Moderate—this is one study, and more research is needed. Always consult with your doctor or a registered dietitian before making major dietary changes, especially if you take medications for blood sugar or other conditions.
This research is most relevant to adults with prediabetes who are looking for dietary strategies to prevent diabetes development. It may also interest people with type 2 diabetes or metabolic syndrome. However, this approach is not recommended for pregnant women, people with certain medical conditions, or those taking specific medications without medical supervision. People who struggle with restrictive diets or have a history of disordered eating should be especially cautious.
If you were to try this approach under medical supervision, you might expect to see improvements in blood sugar markers within 4-12 weeks. However, the long-term sustainability and lasting benefits depend on whether you can maintain this strict diet over time. Most people find very restrictive diets challenging to follow for extended periods.
Want to Apply This Research?
- Track daily carbohydrate intake (aim for under 50g per day on a ketogenic diet) and monitor fasting blood sugar levels weekly if you have a glucose meter. Also track energy levels and any side effects to understand how your body responds to the diet.
- Start by identifying and removing high-carb foods from your diet (bread, pasta, rice, sugary foods) and replacing them with healthy fats (nuts, avocados, olive oil) and proteins (eggs, fish, meat). Use the app to log meals and stay accountable to your carb targets while working with a healthcare provider.
- Establish a baseline of your current blood sugar levels and metabolic markers through your doctor. Then track these same markers every 4-8 weeks while following the diet to see if improvements occur. Also monitor how you feel, your energy levels, and your ability to stick to the diet, as sustainability is key to long-term success.
This research summary is for educational purposes only and should not be considered medical advice. Ketogenic diets are restrictive and may not be appropriate for everyone, particularly those with certain medical conditions, taking specific medications, or with a history of eating disorders. Before starting any new diet, especially one as restrictive as a ketogenic diet, consult with your doctor or a registered dietitian. They can assess whether this approach is safe and appropriate for your individual health situation, monitor your progress, and adjust your plan as needed. If you have prediabetes or diabetes, work with your healthcare team to develop a personalized nutrition strategy that fits your lifestyle and health goals.