Whole-body fat oxidation rate and plasma triacylglycerol concentrations in men consuming an ad libitum high-carbohydrate or low-carbohydrate diet.
BACKGROUND
High-carbohydrate diets may increase plasma triacylglycerol concentrations either by increasing production of triacylglycerols or by reducing their clearance.


OBJECTIVE
We assessed whether the changes in plasma triacylglycerol concentrations induced by dietary interventions were associated with the changes in whole-body fat oxidation rates.


METHODS
In a parallel study, 37 healthy male subjects [body mass index (in kg/m(2)): 28 +/- 5, age: 34 +/- 11 y (x +/- SD)] consumed an ad libitum high-carbohydrate (60% of energy; n = 19) or low-carbohydrate (46% of energy), high-fat (41% of energy, 23% as monounsaturated fatty acids; n = 18) diet for 7 wk. The following variables were measured before and after the dietary interventions: 1) plasma triacylglycerols before and 2, 4, 6, and 8 h after a meal (containing 40% of daily energy needs and 41% fat); 2) indirect calorimetry throughout the 8-h test; and 3) postheparin plasma lipoprotein lipase (phLPL) activity at time 8 h of the test.


RESULTS
The diets induced changes in 1) body weight: -2.5 +/- 2.8 kg (P < 0.01) and -1.7 +/- 3.1 kg (P < 0.05) and 2) fasting plasma triacylglycerols: 0.0 +/- 0.4 mmol/L (NS) and -0.3 +/- 0.3 mmol/L (P < 0.05) for the high-carbohydrate and the low-carbohydrate diets, respectively. In normoinsulinemic subjects (fasting insulin < 100 pmol/L), dietary changes in postprandial triacylglycerols were significantly predicted by changes in phLPL, body weight, respiratory quotient (or fat oxidation), and the type of diet (stepwise multiple linear regression).


CONCLUSIONS
Postprandial plasma triacylglycerol concentrations may depend at least partly on fat oxidation, body weight, and LPL activity.
Landry
Nancy
N
Department of Food Science and Nutrition, Laval University, Québec, Canada.
Bergeron
Nathalie
N
Archer
Roodly
R
Samson
Pierre
P
Corneau
Louise
L
Bergeron
Jean
J
Dériaz
Olivier
O
D000328:Adult; D015992:Body Mass Index; D002153:Calorimetry, Indirect; D004040:Dietary Carbohydrates / Q000008:administration & dosage* / Q000378:metabolism; D004734:Energy Metabolism; D005215:Fasting / Q000378:metabolism; D005229:Fatty Acids, Monounsaturated / Q000008:administration & dosage / Q000378:metabolism; D006801:Humans; D050356:Lipid Metabolism; D008071:Lipoprotein Lipase / Q000378:metabolism; D008297:Male; D009765:Obesity / Q000097:blood / Q000378:metabolism*; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D019518:Postprandial Period / Q000502:physiology; D014280:Triglycerides / Q000097:blood / Q000378:metabolism*; D015431:Weight Loss / Q000502:physiology
D004040:Dietary Carbohydrates; D005229:Fatty Acids, Monounsaturated; D014280:Triglycerides; D008071:Lipoprotein Lipase