Comparison of 2 diets with either 25% or 10% of energy as casein on energy expenditure, substrate balance, and appetite profile.
BACKGROUND
An increase in the protein content of a diet results in an increase in satiety and energy expenditure. It is not clear to what extent a specific type of protein has such effects.


OBJECTIVE
The objective was to compare the effects of 2 diets with either 25% or 10% of energy from casein (25En% and 10En% casein diets), as the only protein source, on energy expenditure, substrate balance, and appetite profile.


METHODS
During a 36-h stay in a respiration chamber, 24 healthy subjects [12 men and 12 women, body mass index (in kg/m(2)) of 22.4 +/- 2.4, age 25 +/- 7 y] received isoenergetic diets according to subject-specific energy requirements: 25En% diet (25%, 20%, and 55% of energy as protein, fat, and carbohydrate, respectively) and 10En% diet (10%, 35%, and 55% of energy as protein, fat, and carbohydrate, respectively) in a randomized crossover design. Three days before the diets began, the subjects consumed a similar diet at home. Energy expenditure, substrate oxidation, and appetite scores were measured.


RESULTS
The 25En% casein diet resulted in a 2.6% higher 24-h total energy expenditure (9.30 +/- 0.24 compared with 9.07 +/- 0.24 MJ/d; P < 0.01) and a higher sleeping metabolic rate (6.74 +/- 0.16 compared with 6.48 +/- 0.17 MJ/d; P < 0.001) than did the 10En% casein diet. With the 25En% casein diet, compared with the 10En% casein diet, the subjects were in positive protein balance (0.57 +/- 0.05 compared with -0.08 +/- 0.03 MJ/d; P < 0.0001) and negative fat balance (-0.83 +/- 0.14 compared with 0.11 +/- 0.17 MJ/d; P < 0.0001), whereas positive carbohydrate balances were not significantly different between diets. Satiety was 33% higher with the 25En% casein diet than with the 10En% casein diet (P < 0.05).


CONCLUSIONS
A 25En% casein diet boosts energy expenditure, protein balance, satiety, and negative fat balance, which is beneficial to body weight management.
Hochstenbach-Waelen
Ananda
A
Department of Human Biology, Nutrition and Toxicology Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands. ananda.waelen@hb.unimaas.nl
Veldhorst
Margriet A B
MA
Nieuwenhuizen
Arie G
AG
Westerterp-Plantenga
Margriet S
MS
Westerterp
Klaas R
KR
D000293:Adolescent; D000328:Adult; D001066:Appetite / Q000187:drug effects* / Q000502:physiology; D001786:Blood Glucose / Q000378:metabolism; D002153:Calorimetry, Indirect; D002364:Caseins / Q000008:administration & dosage*; D018592:Cross-Over Studies; D004044:Dietary Proteins / Q000008:administration & dosage*; D004734:Energy Metabolism / Q000187:drug effects* / Q000502:physiology; D005260:Female; D054439:Ghrelin / Q000097:blood; D052216:Glucagon-Like Peptide 1 / Q000097:blood; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D019894:Peptide YY / Q000097:blood; D012527:Satiation / Q000187:drug effects / Q000502:physiology; D055815:Young Adult
D001786:Blood Glucose; D002364:Caseins; D004044:Dietary Proteins; D054439:Ghrelin; D007328:Insulin; D019894:Peptide YY; D052216:Glucagon-Like Peptide 1