Understanding Ketogenic Diets
Definition and Purpose
Ketogenic diets are characterized by high fat and protein content while being extremely low in carbohydrates. The primary objective of this dietary approach is to encourage the body to burn fats as its main energy source.
Research Findings on Ketogenic Diets
Research has indicated that during periods of energy restriction, as often seen in various diets, the human body tends to reduce its energy expenditure by lowering the resting metabolic rate (RMR). This phenomenon is termed metabolic adaptation, which reflects a decrease in the energy utilized by the body. The RMR represents the energy required for essential bodily functions during rest, such as breathing and cognitive activities.
Long-Term Weight Loss Effects of Ketogenic Diets
Groundbreaking Research
Significant studies have demonstrated that very low-calorie ketogenic diets can lead to weight loss and assist individuals in maintaining this weight loss for up to two years.
Study on Very Low-Calorie Ketogenic Diets
In an investigation aimed at testing the hypothesis that very low-calorie ketogenic diets induce a neutral response regarding resting metabolic rate, researchers published their findings in the journal Nutrition & Metabolism.
Study Results
The study revealed that while the low-calorie ketogenic diets led to weight loss maintenance among obese participants, there was no expected decrease in RMR. The researchers speculated that this neutral RMR response might be attributed to the preservation of lean muscle mass. Their findings suggested that a low-calorie ketogenic diet can help maintain normal resting metabolic levels, preserve lean muscle, and potentially prevent metabolic adaptation, thereby reducing the likelihood of weight regain in obese individuals.
Long-Term Effectiveness of Ketogenic Diets
Comparative Study on Diets
To assess long-term weight loss effectiveness, researchers from Iuliu Hatieganu University of Medicine and Pharmacy in Romania conducted a comparative study between a ketogenic diet and a low glycemic index (GI) nutrigenetic diet, with results published in BMC Nutrition.
Study Methodology
Participants in the ketogenic group restricted carbohydrate intake to a maximum of 35 grams and limited total calories from fat to 10%, with protein tailored to body weight. The low-GI nutrigenetic group underwent DNA testing to create personalized diet plans, also imposing restrictions on carbohydrates and saturated fats. Both groups engaged in regular exercise, and measurements were taken at intervals over 24 weeks, followed by an 18-month monitoring period.
Study Findings
Initial results indicated that the ketogenic diet group lost more weight than the low-GI nutrigenetic group within the first 24 weeks. However, by the 18-month mark, the ketogenic group regained more weight compared to their low-GI counterparts. This suggests that while the ketogenic diet may facilitate initial weight loss, sustained weight management and health benefits could be more effectively achieved through a low-GI nutrigenetic diet.
Effects of Ketogenic Diets on Skin Inflammation
Psoriasis and Inflammation
Psoriasis is characterized by skin inflammation, which can extend to nearby joints and blood vessels. Recent studies indicate that diet significantly influences inflammation control, with ketogenic diets showing potential anti-inflammatory properties.
Study on Skin Inflammation
A study conducted by researchers at Paracelsus Medical University in Salzburg, Austria, aimed to evaluate whether a ketogenic diet could reduce skin inflammation. The findings were published in the Journal of Investigative Dermatology.
Study Results
Mice were fed various diets, including standard diets, ketogenic diets rich in long-chain triglycerides (LCTs) and medium-chain triglycerides (MCTs), some supplemented with omega-3 fatty acids. The results showed that while ketogenic diets high in MCTs aggravated psoriasis symptoms, those primarily consisting of LCTs did not worsen the condition. Dr. Barbara Kofler, a co-lead on the study, noted that a well-balanced ketogenic diet limited to LCTs does not exacerbate skin inflammation, but caution is warranted with high MCT diets due to potential aggravation of existing inflammatory conditions.
Ketogenic Diet and Epilepsy
Influence on Gut Microbiota
The gut microbiota plays a crucial role in human health, significantly influencing metabolic and neurological pathways. It is hypothesized that the ketogenic diet may alter gut microbiota composition to facilitate epilepsy treatment.
Study on Gut Microbiota and Seizures
A study published in Cell investigated how the ketogenic diet affects gut microbiota and whether these changes mediate anti-seizure effects. The research utilized a mouse model of refractory epilepsy to explore the underlying mechanisms.
Study Findings
The study found that within four days, the ketogenic diet increased the abundance of specific bacterial species, leading to an enhanced seizure threshold in mice after electrical stimulation. However, when antibiotics were used to reduce gut microbiota, the seizure threshold reverted to baseline levels. Furthermore, in mice without gut microbiota, the ketogenic diet had no impact on seizure threshold. The researchers identified that adding specific bacterial species could restore seizure protection, highlighting the gut microbiota’s critical role in mediating the ketogenic diet’s therapeutic effects.
Future Research Directions
Ongoing research is essential to further understand the gut microbiota’s influence on human health and the potential for microbe-based therapeutics in treating epilepsy. It is advisable to consult a healthcare professional before making any dietary changes.
References
1. Canton, A., Ordoñez-Mayan, L., … Casanueva, F. F. (2018). Resting metabolic rate of obese patients under very low calorie ketogenic diet. Nutrition & Metabolism, 15(1), 18. https://doi.org/10.1186/s12986-018-0249-z
2. Vranceanu M, Pickering C, Filip L et al. A comparison of a ketogenic diet with a LowGI/nutrigenetic diet over 6 months for weight loss and 18-month follow-up. BMC Nutr. 2020;6(1). doi:10.1186/s40795-020-00370-7
3. Locker F, Leitner J, Aminzadeh-Gohari S et al. The Influence of Ketogenic Diets on Psoriasiform-Like Skin Inflammation. Journal of Investigative Dermatology. 2019. doi:10.1016/j.jid.2019.07.7184
4. Olsen, C.A., Vuong, H.E. Yano, J.M., Liang, Q.Y., Nusbaum, D.J. & Hsiao, E.Y. (2018). The gut microbiota mediates the anti-seizure effects of ketogenic diet. Cell 173, 1728-1741.