Thesis title: Comparison of the Safety and Efficacy of a 3-Month Therapy with a Very Low-Calorie Ketogenic Diet (VLCKD) vs. a Ketogenic Mediterranean Diet in Patients with Obesity
Introduction: Obesity is a chronic and relapsing disease that requires a comprehensive therapeutic approach, including dietary modifications. Among the most studied dietary patterns, an important role is represented by ketogenic diet (KD) and Mediterranean Diet (MedD), the latter recognized by UNESCO as an intangible heritage of humanity and by the FAO as a sustainable dietary model. However, to induce weight loss, a reduction in caloric intake with a relatively high carbohydrate intake, according to the Mediterranean model, produces a modest weight loss compared to a ketogenic approach, which is more effective in the short and medium term. The most widely used KD in the Mediterranean region is the very-low-calorie ketogenic diet (VLCKD), which is highly restrictive in caloric intake and relies on meal replacements. This type of approach, however, is burdened by high costs due to the purchase of replacement meals, and, despite sharing some key elements with the MedD, such as olive oil consumption, it excludes other fundamental components like nuts, red wine, and fish. Some preliminary studies suggest that a Mediterranean-style ketogenic diet (MedKD) may be a valid tool for the treatment of patients with overweight and obesity. The objective of this study was therefore to compare the effectiveness and safety of this dietary approach with the more established VLCKD with meal replacements.
Materials and methods: In this real-world study, patients were assigned to either a VLCKD, highly hypocaloric and including meal replacements, or a slightly hypocaloric ketogenic diet without meal replacements (MedKD), based on personal preference. The study lasted three months, during which all patients adhered to a dietary regime designed to maintain ketosis. Patients were evaluated at baseline and at the end of the study through the collection of anthropometric data and blood tests.
Results: A total of 55 patients (36 women, 19 men) were enrolled in the study, with 27 patients (21 women, 6 men) following the VLCKD and 28 patients (15 women, 13 men) following the MedKD. After dietary intervention, most parameters showed no significant differences between the two groups, both recording significant improvements. Specifically, both dietary approaches demonstrated comparable weight loss (VLCKD -15.2 kg and MedKD -15.4 kg from baseline). Similarly, biochemical markers of metabolic health improved in both groups without substantial differences, with the exception of a more marked improvement in HOMA IR in the MedKD group, which however reported significantly higher values at baseline. Furthermore, no significant difference emerged in terms of tolerability or safety parameters such as sodium, potassium and uric acid. Regarding renal function, the VLCKD group had a slightly lower estimated glomerular filtration rate (eGFR) at baseline compared to the MedKD group (VLCKD 80.8 ±13.7 and MedKD 90.4 ±22.6 with p=0.076), with subsequent improvement after diet. The MedKD group, on the other hand, maintained stable eGFR levels over time.
Conclusions: This study demonstrates that a MedKD without meal replacements or severe caloric restrictions can achieve similar weight loss and metabolic improvements as a VLCKD. Given the importance of personalized dietary therapy for sustainable long-term results and considering the well-documented benefits of the Mediterranean dietary pattern, the adoption of MedKD should be encouraged as part of the therapeutic strategy for obesity management.