A high glycemic meal suppresses the postprandial leptin response in normal healthy adults.
OBJECTIVE
To evaluate the metabolic effects of meals with varying glycemic index (GI).


METHODS
We measured the glucose, insulin and leptin responses to two contrasting breakfast cereals in a group of 10 young healthy volunteers. Meals were provided on two separate occasions in random order after a 12-hour overnight fast, and consisted of 50 g of available carbohydrate from either Corn Flakes (Kellogg's), or Fiber One (General Mills). Blood samples were obtained at rest, and 30, 60, 90 and 120 min after eating. The GI was calculated from the glucose response to the test meal normalized against a 50 g oral glucose load.


RESULTS
The GI for Corn Flakes was 125 +/- 17 units and 49 +/- 8 units for Fiber One(R). These meals were classified as high GI and low GI, respectively, and were significantly different from each other (p < 0.0003). The area under the insulin response curve (AUC) following the low glycemic meal was significantly attenuated compared to the high glycemic meal (14,064 +/- 2,694 vs. 6,828 +/- 1,182 pmol/l.min, p < 0.02). The leptin AUC revealed that circulating leptin was suppressed by the high glycemic meal compared to the low (3.1 +/- 1.5 vs. 9.6 +/- 3.6 ng/ml.min, p < 0.04).


CONCLUSIONS
Lower insulin and higher leptin suggests that low glycemic meals promote a postprandial metabolic milieu that is favorable for reduced food consumption; this may be advantageous in the control of obesity and related disorders including insulin resistance and type 2 diabetes.
Barkoukis
Hope
H
Schwartz Center for Metabolism and Nutrition, Case Western Reserve University School of Medicine and MetroHealth Medical Center, Cleveland, Ohio, USA.
Marchetti
Christine M
CM
Nolan
Brian
B
Sistrun
Sakita N
SN
Krishnan
Raj K
RK
Kirwan
John P
JP
D000293:Adolescent; D000328:Adult; D019540:Area Under Curve; D001786:Blood Glucose / Q000032:analysis; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D020738:Leptin / Q000097:blood*; D008297:Male; D019518:Postprandial Period; D012016:Reference Values
D001786:Blood Glucose; D004040:Dietary Carbohydrates; D020738:Leptin