Differences in glycaemic status do not predict weight loss in response to hypocaloric diets in obese patients

The aim of our study was to detect differences in weigth loss with a hypocaloric diet in obese patients depending on their glycaemic status.

A population of 76 obesity outpatients was analysed in a prospective way. The following variables were specifically recorded at basal time and after 3 months of hypocaloric diet (1200 kcal/day): weight, blood pressure, body mass index (BMI), waist circumference, and waist-hip ratio. Basal glucose, insulin, fibrinogen, cortisol, c-reactive protein, total cholesterol, LDL cholesterol, HDL cholesterol and triglycerides blood levels were measured. HOMA was calculated. An indirect calorimetry, tetrapolar electrical bioimpedance and a serial assessment of nutritional intake with 3 days written food records were performed.

The mean age was 46.9 +/- 17.1 years and the mean BMI 34.6 +/- 5.3. All subjects were weight stable during the 2 weeks period preceding the study (body weight change, 0.3 +/- 0.1 kg). Anthropometric measurements showed an average waist circumference (108.7 +/- 15.7 cm), waist-to-hip ratio (0.93 +/- 0.11), and average weight (88.7 +/- 16.9 kg). Bipolar body electrical bioimpedance showed a fat mass of 37 +/- 12.3 kg. Indirect calorimetry showed a resting metabolic rate (RMR) (1674.3 +/- 392 kcal/day). Patients were divided in to two groups by glycaemic status (group I: normal glycaemic metabolism, fasting glucose levels <109 mg/dl; n = 50) and (group II: impaired glycaemic metabolism, fasting glucose levels >110 mg/dl, n = 26). Waist circumference (I: 108 +/- 17.1cm vs. 104.6 +/- 16.7 cm; P < 0.05) and (II: 113.6 +/- 9.8 cm vs. 110.9 +/- 8.9 cm; P < 0.05), weight (I: 90.6 +/- 19.2 kg vs. 86.3 +/- 18.6 kg:P < 0.05) and (II: 89.2 +/- 11.3 kg vs. 86.4 +/- 11.6 kg: P < 0.05) and BMI (I: 34.2 +/- 5.6 vs. 33.7 +/- 5.5; P < 0.05) and (II: 34.8 +/- 4.2 vs. 34.2 +/- 4.6; P < 0.05) improved in both groups with hypocaloric diet. Blood systolic pressure, total cholesterol and LDL cholesterol improved in both groups, without statistical differences. In group II improved glucose levels and HOMA index, too. Patients of group II had higher systolic blood pressure, glucose, total cholesterol, LDL cholesterol, triglycerides, lipoprotein (a), RCP levels and HOMA index than patients in group I. ANOVA analysis did not show differences among weight loss in tertiles of HOMA and glucose.

Ability to lose weight on a hypocaloric diet over a 3-month time period does not vary in obese patients as a function of glycaemic status. Improvement in cardiovascular risk factors is not related with glycaemic status, too.