This study is open label, with one arm only. In this study will be enrolled patients with obesity (BMI more than 30). Aim of the study is to determine the influence (if any) of a very low calorie ketogenic diet (VLCKD) on gut permeability and liver steatosis.

The first objective is to examine the influence of obesity on the prevalence and severity of impaired intestinal permeability and hepatic steatosis.

Intestinal permeability means the ability of the intestinal barrier to block the passage of substances potentially harmful to our body.

The second objective is to evaluate whether a low-calorie and ketogenic dietary intervention, lasting 6 weeks, can change intestinal permeability and hepatic steatosis

Inclusion Criteria:

1. BMI ≥ 30 Kg/m2 or abdominal circumference (waist) >94 cm in men and >80 cm in women (IDF criteria for the definition of abdominal obesity) with or without the features that characterize the metabolic syndrome
2. Age range between 18 and 70 years, both sexes
3. Diagnosis of hepatic steatosis, formulated on the basis of fibroscan [CAP (controlled attenuation parameter) > 238 dB/m(decibel/meter)], and other recognized criteria (FLI - Fatty Liver Index , FIB-4 - Fibrosis-4 index, NFS - NAFLD fibrosis score).

Exclusion Criteria:

1. Normal and underweight subjects
2. Presence of any pathology that may affect the presence of altered intestinal permeability or steatosis, apart from pathologies that represent inclusion criteria
3. Treatment with any device, pharmacological or not, that can affect intestinal permeability and liver metabolism and, therefore, the presence of steatosis
4. Pregnancy or lactation