Effects of a lifestyle intervention in metabolically benign and malign obesity
We and others recently characterised metabolically benign or healthy obesity (MHO). In the present study we investigated whether a lifestyle intervention is sufficient to place obese insulin-resistant (OIR) individuals in a position where the possible metabolic consequences are similar to those for MHO individuals. A total of 262 non-diabetic individuals participated in a 9 month lifestyle intervention programme. Obese individuals (BMI ≥ 30.0 kg/m2) were stratified, based on their insulin sensitivity (IS) estimated from an OGTT, into MHO (IS in the upper quartile, n = 26) and OIR (IS in the lower three quartiles, n = 77). Total body and visceral fat were measured by magnetic resonance (MR) tomography and liver fat by 1H-MR spectroscopy. During the intervention, visceral fat decreased significantly in both groups (both p ≤ 0.009), whereas total body and liver fat decreased only in the OIR group (p < 0.0001; MHO p = 0.12 for total body fat and p = 0.47 for liver fat). IS improved in the OIR group (p < 0.0001), but remained essentially unchanged in the MHO group (p = 0.30). However, despite the significant increase in the OIR group, IS at follow-up barely exceeded 50% of the IS of the MHO group (OIR 9.30 ± 0.53 arbitrary units [AU]; MHO 16.41 ± 1.05 AU; p < 0.0001). IS improves during the lifestyle intervention in OIR individuals. However, it does not reach a level where adequate protection from type 2 diabetes and cardiovascular disease is expected. Thus, stratification of obese individuals based on their metabolic phenotype is important to identify those who are likely to need early pharmacological treatment in addition to the lifestyle intervention.