Particle size, satiety and the glycaemic response.

OBJECTIVE

This study investigated the hypothesis that the smaller the particle size of the food, the higher the glycaemic-insulin response and the lower the satiety rating.

DESIGN AND SUBJECTS

Ten healthy subjects consumed equal carbohydrate portions of four test meals of equivalent nutritional composition based on four different grades of wheat: whole grains, cracked grains, coarse and fine wholemeal flour.

RESULTS

The mean overall plasma glucose response (area under the curve: AUC) was highest for the fine flour meal (4205 +/- 451 mmol/l.120 min), followed by the coarse flour and cracked grain meals and lowest for the whole grain meal (1524 +/- 190 mmol/l.120 min). Insulin responses showed the same ranking but satiety responses were the reverse, the fine flour meal giving the lowest satiety response [AUC: 231.4 +/- 31.6 rating scale (RS) units.120 min] and the whole grain meal the highest response (AUC: 318.4 +/- 29.3 RS units.120 min). Total insulin responses (AUC) were significantly associated with subjective satiety when analyses on an individual basis (analysis of covariance coefficient = -0.024, P < 0.04) such that for every 1000 unit increase in AUC insulin, satiety decreased by 24 units (13% on average).

CONCLUSION

The results suggest that the processing of cereals is not only a major determinant of the glycaemic and insulin response but also affects the levels of postprandial satiety.