Very Low Calorie Ketogenic Diet: What Effects on Lipid Metabolism?

PURPOSE OF REVIEW: This review aims to critically examine how VLCKD affects plasma lipoprotein, lipid and cholesterol metabolism. Cardiovascular disease is a worldwide health problem affecting millions of people and leading to high rates of mortality and morbidity. There is a well-established association between cardiovascular disease and circulating cholesterol. Various dietary recommendations are currently available for the management of dyslipidemia. RECENT FINDINGS: The very low-calorie ketogenic diet (VLCKD) is becoming increasingly popular as a treatment option for several pathological conditions, including dyslipidemia. In addition to being low in calories, the VLCKD's main feature is its unique calorie distribution, emphasizing a reduction in carbohydrate consumption in favor of fat as the primary calorie source. Lowering calorie intake through a VLCKD can reduce the endogenous production of cholesterol. However, if the foods consumed are from animal sources, dietary cholesterol intake may increase due to the higher fat content of animal products. When combined, these dietary practices may have opposing effects on plasma cholesterol levels. Studies investigating the impact of VLCKD on plasma cholesterol and low-density lipoprotein cholesterol levels report contradictory findings. While some studies found an increase in low-density lipoprotein cholesterol levels, others showed a decrease in total cholesterol and low-density lipoprotein cholesterol, along with an increase in high-density lipoprotein cholesterol.

Obesity and Obesity-Related Thyroid Dysfunction: Any Potential Role for the Very Low-Calorie Ketogenic Diet (VLCKD)?

PURPOSE OF REVIEW: This review aims to explore in-depth the different aspects of the association between very low-calorie ketogenic diet (VLCKD), obesity and obesity-related thyroid dysfunction. RECENT FINDINGS: The VLCKD, proposed as a non-pharmacological strategy for the management of certain chronic diseases, is becoming increasingly popular worldwide. Initially used to treat epilepsy, it has been shown to be effective in controlling body weight gain and addressing various pathophysiological conditions. Research has shown that a low-calorie, high-fat diet can affect thyroid hormone levels. Weight loss can also influence thyroid hormone levels. Studies have suggested that long-term use of VLCKD for refractory epilepsy may be related to the development of hypothyroidism, with an effect seen in various populations. In particular, women with obesity following VLCKD tend to have reduced T3 levels. We propose further research to unravel the underlying mechanisms linking VLCKD to obesity and obesity-related thyroid dysfunction.

The Impact of a Very-Low-Calorie Ketogenic Diet in the Gut Microbiota Composition in Obesity.

The very-low-calorie KD (VLCKD) is characterized by a caloric intake of under 800 kcal/day divided into less than 50 g/day of carbohydrate (13%) and 1 to 1.5 g of protein/kg of body weight (44%) and 43% of fat. This low carbohydrate intake changes the energy source from glucose to ketone bodies. Moreover, clinical trials have consistently shown a beneficial effect of VLCKD in several diseases, such as heart failure, schizophrenia, multiple sclerosis, Parkinson's, and obesity, among others. The gut microbiota has been associated with the metabolic conditions of a person and is regulated by diet interactions; furthermore, it has been shown that the microbiota has a role in body weight homeostasis by regulating metabolism, appetite, and energy. Currently, there is increasing evidence of an association between gut microbiota dysbiosis and the pathophysiology of obesity. In addition, the molecular pathways, the role of metabolites, and how microbiota modulation could be beneficial remain unclear, and more research is needed. The objective of the present article is to contribute with an overview of the impact that VLCKD has on the intestinal microbiota composition of individuals with obesity through a literature review describing the latest research regarding the topic and highlighting which bacteria phyla are associated with obesity and VLCKD.

Effectiveness and Safety of a Very Low-Calorie Ketogenic Diet on Weight Regain Following Bariatric Surgery.

PURPOSE: Obesity is one of the major public health problems worldwide and bariatric surgery is considered the gold standard treatment for severe obesity. Although the literature supports the safety and efficacy of the very low-calorie ketogenic diet (VLCKD) in patients with obesity, there is no study analyzing the use in case of failure or weight regain after bariatric surgery. This work has the purpose of assessing the response to a VLCKD (Pnk® method) in this population. METHODS: We have conducted an observational, retrospective, and descriptive study with the analysis of medical charts of private offices where patients were examined between 2014 and 2019, totalizing 11 participants who underwent Roux-en-Y gastric bypass (RYGB) without a reduction of 50% in body weight excess or any weight regain after the surgery. The patients followed the first stage of a commercial weight loss program (Pnk® method) which consists of a VLCKD (600-800 kcal/day), low in carbohydrates and lipids. RESULTS: A significant reduction was observed (p-value < 0.05) in weight, body mass index (BMI), abdominal circumference (AC), and glycated hemoglobin (A1C) post-ketogenic diet. Uric acid, transaminases, urea, and creatinine values did not show differences between pre- and post-ketosis. During the course of the study, no serious adverse events were reported. CONCLUSION: This study has shown that the ketogenic diet can be recommended as an effective and safe treatment for patients who progressed with insufficient weight loss or regain after bariatric surgery.