This is what the Keto Diet does to your body...

Ketogenic diets, which involve drastically reducing carbohydrate intake and increasing fat intake, can have significant health benefits for some individuals. These diets have been used to treat severe diabetes and have been credited with dramatic improvements. However, they are not suitable for everyone, as they can lead to a lack of fiber for gut microbes and may not be sustainable long-term for some people. Christopher Gardner, a leading nutritional researcher at Stanford University, shares the results of a landmark clinical trial on keto diets, published in the American Journal of Clinical Nutrition. While the diet can lead to weight loss, it is important to note that not all ketogenic diets are created equal, and a healthy version would require careful planning to ensure adequate nutrient intake. The biggest misconception about the ketogenic diet is that it is a high-meat diet, but it is actually a high-fat diet. The body does not stop processing carbs entirely when on a ketogenic diet. Overall, the science on keto diets is complex, and it is essential to consider individual health needs and preferences before deciding if this diet is right for you.

The body normally burns a combination of carbohydrates and fats for energy through a process called the Krebs cycle or TCA cycle. However, when carbohydrate intake is significantly reduced, the body enters a state of ketosis, where it produces ketones from stored fat as an alternative energy source. This state has gained popularity as a potential healthier alternative to the traditional recommendation of burning carbs and fats together. The interest in ketosis today can be attributed to ongoing debates about the optimal macronutrient composition of diets, with some suggesting that very low carbohydrate intake may be beneficial. The literature on low fat and low carb diets is complex and often inconsistent due to varying definitions and approaches. Ultimately, the decision between different dietary strategies depends on individual health goals and preferences.

The ketogenic diet is an extreme dietary approach that significantly limits carbohydrate intake, often aiming for less than 50 grams per day. This is a drastic reduction from the typical Western diet, which often contains several hundred grams of carbs daily. The ketogenic diet is rooted in the belief that a low-carb, high-fat diet can lead to better health outcomes, following earlier dietary trends that emphasized reducing fat intake. However, conducting large-scale, randomized controlled trials to definitively establish the health benefits of such diets is challenging due to the difficulty of getting people to stick to specific diets and the potential for confounding factors. The American Journal of Clinical Nutrition recently published a study on this topic, and we will provide links to it in the show notes for those interested.

While a randomized control trial comparing a ketogenic diet to a Mediterranean diet yielded strong scientific results, it's essential to remember that one study doesn't answer all the questions. The study, which compared diets with similarities in above ground vegetables, absence of added sugar and refined grains, but differing in carbohydrate intake, found that the ketogenic diet required a significantly lower carbohydrate intake, effectively eliminating whole grains, beans, fruits, and legumes. However, these food groups are key sources of fiber for a healthy microbiome, and eliminating them runs counter to most public health recommendations. So, while the study provides valuable insights into the comparison of these two diets, it's crucial to consider the limitations and implications for other dietary options.

The KetoMed study, which is a well-formulated ketogenic diet combined with elements of the Mediterranean diet, showed similar blood glucose benefits for people with type 2 diabetes or prediabetes when compared to a more traditional Mediterranean diet in a 12-week study. Both diets led to weight loss and improvements in glycosylated hemoglobin, blood pressure, blood lipids, and liver enzymes. However, the ketogenic diet's absence of whole grains, fruits, and beans stood out as a key difference, and further research is needed to determine if this absence provides additional benefits. Despite skepticism, the study showed that both diets were effective in managing blood sugar levels.

Both the Mediterranean and ketogenic diets led to weight loss and improvements in various health markers during the 12-week study. However, the ketogenic diet was associated with a statistically significant increase in LDL cholesterol levels, while the Mediterranean diet led to a decrease. Conversely, triglycerides went down more drastically in the ketogenic diet than in the Mediterranean one. This is surprising because, as explained, when you eat a high carbohydrate, low-fat diet, your blood triglycerides go up due to the excessive carbs being converted into fats, not the fat you're eating. Regarding the long-term sustainability of these diets, the study design included food delivery for the first 4 weeks of each phase to ensure maximum adherence. The results from the last 8 weeks, when participants prepared their own meals, will provide insights into the real-world sustainability of both diets. Another important consideration is the potential impact on nutrient intake and the microbiome, as the ketogenic diet is inherently lower in fiber. Further research is ongoing to address these questions.

While both the ketogenic and Mediterranean diets led to weight loss during the study, adherence to the diets varied greatly among individuals. When provided with food, both groups averaged around 7.5 out of 10 for diet adherence. However, when left to their own devices, the groups showed vastly different results. The keto group had some individuals who did extremely well, while others struggled. In contrast, the Mediterranean group had a more consistent, but still imperfect, adherence to the diet. Interestingly, when asked about their diets 12 weeks after the study, participants reported that they had reverted to their old habits, with the Mediterranean diet being more sustainable for most. Ultimately, the study raises important questions about the level of strictness required to make the ketogenic diet worthwhile, as the benefits may not be sustainable for all individuals.

Maintaining ketosis is crucial for experiencing the health benefits of a ketogenic diet, such as improved insulin secretion and insulin resistance. However, many people in a study had difficulty achieving and maintaining ketosis due to consuming more carbohydrates than necessary. While some individuals with diabetes have reported positive results from long-term adherence to ketogenic diets, it may not be the best option for everyone. For those considering trying a ketogenic diet, it may be helpful to eliminate added sugar and refined grains to anchor psychologically to a low-carb lifestyle. However, a Mediterranean diet, which is easier to stick with long-term, may offer more options and flexibility for social events. It's important to note that a ketogenic diet is highly restrictive and may lead to nutrient deficiencies if followed long-term, particularly in fiber and microbiome health.

A ketogenic diet, which is a low-carb diet, can have an impact on the microbiome. While some short-chain fatty acids, including ketones, can be produced from the diet itself, the absence of fiber from whole grains, fruits, and beans results in a significant decrease in fiber intake. This could potentially have longer-term effects on inflammation, immune profiles, and immune function. However, the exact impact on the microbiome is still being studied, and longer-term studies are needed to fully understand the effects. There is no evidence that following a ketogenic diet permanently damages the body's ability to process carbs, as the necessary enzymes for carbohydrate metabolism remain present. It's important to note that while the ketogenic diet may have benefits for some individuals, it may not be suitable for everyone, and potential nutrient deficiencies should be considered.

Both the ketogenic and Mediterranean diets showed weight loss and health improvements in a study. However, the sustainability of the ketogenic diet was a concern, as most participants were no longer in a state of ketosis by week 12. The diet's impact on certain nutrients and the microbiome is also a concern due to the lack of fiber. Overall, while some individuals may find the ketogenic diet effective, it's likely not a viable option for most people. The popularity of the ketogenic diet may be due to misunderstandings about its high-fat, not high-meat, nature. Christopher Gardner, the study's lead author, emphasized the importance of personalized nutrition and encouraged individuals to explore options like ZOE's at-home test to understand their unique nutritional needs.