Appetite hormones and energy intake in obese men after consumption of fructose, glucose and whey protein beverages

doi:doi:10.1038/sj.ijo.0803665

Abstract

Objective:

To investigate appetite responses over 4 h to fructose beverages in obese men, relative to glucose and whey protein. Second, to investigate the effect of combining whey and fructose on postprandial appetite hormones.

Design:

Randomized, double-blind crossover study of four beverages (1.1 MJ) containing 50 g of whey, fructose, glucose or 25 g whey+25 g fructose. Blood samples and appetite ratings were collected for 4 h then a buffet meal was offered.

Subjects:

Twenty-eight obese men (age: 57.0 plusminus 1.6 years, body mass index: 32.50.6 kg/m²)

Measurements:

Plasma ghrelin (total), glucagon-like peptide-1 (GLP-1 7–36), cholecystokinin-8, glucose, insulin and appetite ratings were assessed at baseline and 30, 45, 60, 90, 120, 180, 240 min after beverages, followed by measurement of ad libitum energy intake.

Results:

Fructose produced lower glycaemia and insulinaemia compared to the glucose treatment (P<0.0001); whereas postprandial ghrelin, GLP-1 and cholecystokinin responses were similar after both treatments. Whey protein produced a prolonged (2–4 h) suppression of ghrelin (P=0.001) and elevation of GLP-1 (P=0.002) and cholecystokinin (P=0.003) that were reduced when combined with fructose, while glucose and insulin responses were similar. Energy intake after 4 h was independent of beverage type (glucose 4.7 plusminus 0.2 MJ; fructose 4.90.3 MJ; whey 4.60.3 MJ; whey/fructose 4.80.3 MJ; P>0.05).

Conclusion:

In obese men, fructose- and glucose-based beverages had similar effects on appetite and associated regulatory hormones, independent of the differing glycaemic and insulinaemic responses. The contrasting profile of plasma ghrelin, GLP-1 and cholecystokinin after whey protein consumption did not impact on ad libitum intake 4 h later and was attenuated when 50% of whey was replaced with fructose.

Keywords:

fructose, protein, appetite, ghrelin, GLP-1

Original Article