Post-prandial hyperglycemia has been shown to suppress appetite by modulating brain activity. We have observed that after weight loss, obese (OB) individuals exhibit increased hunger and decreased brain responses in regions associated with appetite control during hyperglycemia. This study aimed to investigate whether short-term weight loss can affect brain regulation of food intake during hyperglycemia in obesity.
14 healthy OB subjects (8F/6M, age 46±8 years, BMI 33.4±3.5 kg/m2) underwent functional MRI (fMRI) during a hyperglycemic clamp (200 mg/dl). Blood-oxygen-level-dependent (BOLD) brain activity was assessed while subjects viewed high calorie food pictures. Hunger was rated before and after the scan. Immediately after the scan, subjects had an ad libitum test meal. The study was repeated after an 8 week reduced calorie diet that caused 2.9±2.8 kg weight loss (p=0.002).
Hunger significantly increased during the fMRI-clamp study after the diet (p=0.036), but not before the diet. Total calorie intake at the test meal nearly doubled after weight loss (978±492 vs. 1895±189 kcal, p<0.001). This was associated with a significant decrease in brain activity in regions modulating feeding behavior after the diet (p<0.001, Figure 1). These data suggest that short-term dieting diminishes glucose-induced neural control of appetite and food consumption, which may have important implications for weight loss maintenance.
W. Lam: None. D. Seo: None. C. Lacadie: None. C.P. Schmidt: None. S. Rosenberg: None. H. Hoang: None. J. Hwang: None. T. Constable: None. M. Savoye: None. R. Sinha: None. R. Sherwin: Other Relationship; Self; QuintilesIMS, MannKind Corporation. Research Support; Self; Regeneron Pharmaceuticals, Inc.. Other Relationship; Self; ICON plc. R. Belfort-DeAguiar: Research Support; Self; GlaxoSmithKline plc..