Fig. 1.

Metabolic parameters before and after very low-calorie ketogenic diet (VLCKD). The pink rectangles indicate the range of values considered abnormal (≥100 mg/dl for glycaemia, ≥25 µIU/ml for insulin, ≥2.5 for HOMA index, ≥4 ng/ml for C-peptide, and ≥11 pmol/l for proinsulin). At enrollment, values of insulin (b), HOMA index (c), C-peptide (d), and proinsulin (e) were outside the normal range in all patients. With the exception for proinsulin/insulin ratio (f), all values decreased significantly after VLCKD compared to their respective values at enrollment (a–e). The end of diet glycaemia (a), insulin (b), C-peptide (d), and proinsulin (e) levels returned within the normal range in all patients