Effect of different macronutrients in excess on gastric sensory and motor functions and appetite in normal-weight, overweight, and obese humans.
BACKGROUND
The effects of supplementation with different macronutrients on gastric sensory and motor functions are unclear.


OBJECTIVE
We aimed to compare the effects of 2 wk of supplementation with different classes of macronutrients on gastric function, satiation, and appetite in healthy and overweight subjects.


METHODS
In a parallel-group, double-blind study, 52 (14 men, 38 women) healthy normal-weight, overweight, and obese participants [body mass index (BMI; in kg/m(2)): 19.4-47.0] aged 18-64 y were randomly assigned to consume different isocaloric diets (n = 13 per diet group) adjusted for BMI and activity level. The standard diet provided 20% of energy as protein, 30% as fat, and 50% as carbohydrate. The high-protein, high-fat, and high-carbohydrate diets contained 500 additional kcal in each nutrient class. On 3 separate days, we measured gastric emptying of solids, gastric volumes, postprandial symptoms, appetite, and food choice with validated methods. Age, sex, BMI, and baseline satiation were covariates in the analysis of covariance.


RESULTS
Fat supplementation was associated with increased maximum tolerated volume (MTV) in subjects with a high baseline MTV (P < 0.05), irrespective of BMI. Gastric emptying and volumes, postprandial symptoms, total calories, and food choices at an ad libitum meal were not significantly different after each dietary preload. Fasting gastric volumes tended to be higher with the high-fat than with the high-carbohydrate or high-protein diets (P <or= 0.1). Gastric emptying and volumes and satiation were not significantly different between the BMI categories (< and >30).


CONCLUSIONS
Supplementation with 500 kcal fat in excess of required calories for 2 wk increased food tolerance in healthy normal-weight and obese subjects with a high baseline MTV without significantly changing gastric motor functions.
Park
Moo In
MI
Clinical Enteric Neuroscience Translational and Epidemiological Research Group, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
Camilleri
Michael
M
O'Connor
Helen
H
Oenning
Lavonne
L
Burton
Duane
D
Stephens
Debra
D
Zinsmeister
Alan R
AR
D000293:Adolescent; D000328:Adult; D001066:Appetite / Q000187:drug effects* / Q000502:physiology; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology*; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000494:pharmacology*; D004044:Dietary Proteins / Q000008:administration & dosage / Q000494:pharmacology*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005746:Gastric Emptying / Q000187:drug effects* / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D009475:Neurons, Afferent / Q000502:physiology; D009765:Obesity / Q000503:physiopathology*; D012527:Satiation / Q000187:drug effects / Q000502:physiology; D013270:Stomach / Q000294:innervation
D004040:Dietary Carbohydrates; D004044:Dietary Proteins