Energy intake, ghrelin, and cholecystokinin after different carbohydrate and protein preloads in overweight men.
BACKGROUND
Dietary proteins appear to be more satiating than carbohydrate. The mechanism and effect of protein and carbohydrate type are unclear.


OBJECTIVE
The objective of the study is to compare the acute effect of different proteins and carbohydrates on indicators of appetite and appetite regulatory hormones.


METHODS
This is a randomized cross-over study of four orally consumed preloads followed by blood sampling (+15, 30, 45, 60, 90, 120, 180 min), then a buffet meal.


METHODS
The study was carried out in an outpatient clinic.


METHODS
Nineteen overweight (body mass index 32.1 +/- 0.9 kg/m(2)) men participated.


METHODS
Liquid preloads (1 MJ) contained whey (55 g), casein (55 g), lactose (56 g), or glucose (56 g).


METHODS
Plasma ghrelin, cholecystokinin (CCK), insulin, glucose and amino acids, gastric emptying rate (plasma paracetamol), appetite rating (visual analog scale), and ad libitum energy intake were the main outcome measures.


RESULTS
Energy intake was 10 +/- 3% higher after the glucose preload compared with lactose and protein preloads (P < 0.05), which were predicted by ghrelin at 120 min (P < 0.05). CCK was 71 +/- 6% higher 90 min after the protein preloads compared with glucose and lactose (P < 0.05), which predicted appetite at 180 min (P < 0.05). There was a small increase in branched chain amino acids after the whey preload compared with casein (P < 0.01), but this was independent of appetite and energy intake.


CONCLUSIONS
Acute appetite and energy intake are equally reduced after consumption of lactose, casein, or whey compared with glucose, which was consistent with differences in plasma ghrelin. Higher CCK responses after proteins correlated with satiety but did not affect energy intake.
Bowen
Jane
J
Commonwealth Scientific and Industrial Research Organization, Human Nutrition, P.O. Box 10041 BC, Adelaide SA 5000, Australia. jane.bowen@csiro.au
Noakes
Manny
M
Trenerry
Craige
C
Clifton
Peter M
PM
D000082:Acetaminophen / Q000493:pharmacokinetics; D000328:Adult; D000596:Amino Acids / Q000097:blood; D018712:Analgesics, Non-Narcotic / Q000493:pharmacokinetics; D001786:Blood Glucose / Q000378:metabolism; D002364:Caseins / Q000493:pharmacokinetics; D002766:Cholecystokinin / Q000097:blood*; D018592:Cross-Over Studies; D004032:Diet; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D004044:Dietary Proteins / Q000494:pharmacology*; D002149:Energy Intake / Q000502:physiology*; D054439:Ghrelin; D005947:Glucose / Q000494:pharmacology; D006801:Humans; D007328:Insulin / Q000097:blood; D007785:Lactose / Q000494:pharmacology; D008297:Male; D008894:Milk Proteins / Q000493:pharmacokinetics; D009765:Obesity / Q000378:metabolism*; D036361:Peptide Hormones / Q000097:blood*; D012044:Regression Analysis; D012528:Satiety Response / Q000187:drug effects; D000067816:Whey Proteins
D000596:Amino Acids; D018712:Analgesics, Non-Narcotic; D001786:Blood Glucose; D002364:Caseins; D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D054439:Ghrelin; D007328:Insulin; D008894:Milk Proteins; D036361:Peptide Hormones; D000067816:Whey Proteins; D000082:Acetaminophen; D002766:Cholecystokinin; D005947:Glucose; D007785:Lactose