The influence of the type of dietary fat on postprandial fat oxidation rates: monounsaturated (olive oil) vs saturated fat (cream).
OBJECTIVE
To compare postprandial whole-body fat oxidation rates in humans, following high-fat (43% of total energy) mixed breakfast meals, of fixed energy and macronutrient composition, rich in either monounsaturated fat (MUFA) from extra virgin olive oil or saturated fat (SFA) from cream.


METHODS
Paired comparison of resting metabolic rate (RMR), thermic effect of a meal and substrate oxidation rates following consumption of isocaloric breakfast meals, differing only in the type of fat, administered in random order 1-2 weeks apart.


METHODS
Fourteen male volunteers, body mass index (BMI) in the range 20-32 kg/m(2), aged 24-49 y and resident in Melbourne, Australia, were recruited by advertisement in the local media or by personal contact.


METHODS
Body size and composition was determined by anthropometry and dual energy X-ray absorptiometry (DEXA). Indirect calorimetry was used to measure RMR, thermic effect of a meal, post-meal total energy expenditure and substrate oxidation rate. Blood pressure and pulse rates were measured with an automated oscillometric system. Fasting and 2 h postprandial glucose and insulin concentrations and the fasting lipid profile were also determined.


RESULTS
In the 5 h following the MUFA breakfast, there was a significantly greater postprandial fat oxidation rate (3.08+/-4.58 g/5 h, P=0.017), and lower postprandial carbohydrate oxidation rate (P=0.025), than after the SFA breakfast. Thermic effect of a meal was significantly higher (55 kJ/5 h, P=0.034) after the MUFA breakfast, in subjects with a high waist circumference (HWC > or = 99 cm) than those with a low waist circumference (LWC<99 cm). This difference was not detected following the SFA breakfast (P=0.910).


CONCLUSIONS
If postprandial fat oxidation rates are higher after high MUFA, rather than SFA meals, then a simple change to the type of dietary fat consumed might have beneficial effects in curbing weight gain in men consuming a relatively high-fat diet. This may be particularly evident in men with a large waist circumference.
Piers
L S
LS
Menzies School of Health Research, Casuarina, Australia. sunil.piers@menzies.edu.au
Walker
K Z
KZ
Stoney
R M
RM
Soares
M J
MJ
O'Dea
K
K
D015502:Absorptiometry, Photon; D000328:Adult; D000818:Animals; D001481:Basal Metabolism; D001786:Blood Glucose / Q000032:analysis; D001823:Body Composition; D001824:Body Constitution; D015992:Body Mass Index; D002153:Calorimetry, Indirect; D003611:Dairy Products; D004041:Dietary Fats / Q000494:pharmacology*; D002149:Energy Intake; D004734:Energy Metabolism; D005215:Fasting; D005227:Fatty Acids / Q000378:metabolism*; D005502:Food; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000378:metabolism; D000069463:Olive Oil; D010084:Oxidation-Reduction; D010938:Plant Oils / Q000494:pharmacology*; D022722:Thermogenesis
D001786:Blood Glucose; D004041:Dietary Fats; D005227:Fatty Acids; D007328:Insulin; D008055:Lipids; D000069463:Olive Oil; D010938:Plant Oils