Substrate utilization in man: effects of dietary fat and carbohydrate

Substrate utilization in man: effects of dietary fat and carbohydrate. Verboeket-van de Venne WP, Westerterp KR, ten Hoor F. Department of Human Biology, University of Limburg, Maastricht, The Netherlands. In man there is evidence that the ability to adjust fat oxidation to fat intake is less effective than the ability to adjust carbohydrate and protein oxidation to carbohydrate and protein intake. The short-term (3-day) effects of a low-fat (LF), mixed (M), and high-fat (HF) diet on human substrate balances were studied using a respiration chamber. Subjects were 14 young female students classified by means of their scores on psychometric questionnaires as "restrained" or "unrestrained" eaters. Subjects were in energy balance, ie, the mean difference between energy intake (EI) and energy expenditure (EE) was 86 +/- 85 kJ/d. The fat content of the food significantly influence the 24-hour respiratory quotient (RQ) and nonprotein respiratory quotient (NPRQ). For both the LF and M diets, the 24-hour RQ was significantly lower than the food quotient (FQ), whereas the RQ on the HF diet was not different from the FQ. Oxidation of fat and carbohydrate significantly increased with, respectively, an increasing fat and carbohydrate content of the diet for both restrained- and unrestrained-eating subjects. Restrained-eating subjects showed a decreased fat oxidation compared with unrestrained eaters in response to a HF diet, resulting in a positive fat balance for restrained-eating subjects. On a LF diet, fat balance was negative for both groups of subjects, indicating net endogenous fat oxidation. In conclusion, restrained-eating subjects have more difficulty in the handling of a HF diet, possibly explaining their higher susceptibility to becoming obes

Daily physical activity assessment: comparison between movement registration and doubly labeled water.

Daily physical activity assessment: comparison between movement registration and doubly labeled water. Bouten CV, Verboeket-van de Venne WP, Westerterp KR, Verduin M, Janssen JD. Department of Human Biology, University of Limburg, Maastricht, The Netherlands. [email protected] The use of movement registration for daily physical activity assessment was evaluated during a 7-day period in 30 free-living subjects. Body movement was registered with a Tracmor motion sensor consisting of a triaxial accelerometer and a data unit for on-line processing of accelerometer output over 1-min intervals. Average Tracmor output was correlated against four different energy estimates: 1) average daily metabolic rate (ADMR), determined with doubly labeled water; 2) ADMR-sleeping metabolic rate (SMR; determined in a respiration chamber); 3) (ADMR-SMR) per kilogram of body mass; and 4) the overall physical activity level (PAL = ADMR/SMR). The highest correlation was found for the relationship between Tracmor output and PAL (r = 0.58). After correction for Tracmor values arising from vibrations produced by transportation means, this correlation was improved to 0.73. There was no difference between Tracmor output and PAL in discriminating between overall activity levels with "low" (PAL 1.85) intensity. It is concluded that the Tracmor can be used in free-living subjects to distinguish among interindividual as well as intraindividual levels of daily physical activity

Effects of dietary fat and carbohydrate exchange on human energy metabolism

Effects of dietary fat and carbohydrate exchange on human energy metabolism. Yerboeket-van de Venne WP, Westerterp KR. Department of Human Biology, University of Limburg, Maastricht, The Netherlands. Short-term effects of low-fat (10% fat energy), mixed (30% fat energy), and high-fat (50% fat energy) diets on 24-h energy expenditure, and on its components sleeping metabolic rate, diet induced thermogenesis and energy expenditure for physical activity were studied for 3 days using a respiration chamber in twelve normal-weight female volunteers classified as restrained or unrestrained eaters. There were no significant differences in any of the four measures between the restrained and unrestrained eating subjects on any of the diets. Within the group of restrained eaters, 24-h energy expenditure was significantly decreased during consumption of the mixed diet (8.21 +/- 0.21 MJ/d; p < 0.01) and tended to be decreased on the high-fat diet (8.22 +/- 0.25 MJ/d; p = 0.055), relative to the low-fat diet (8.58 +/- 0.21 MJ/d). Diet composition had no effect on 24-h energy expenditure in the women with unrestrained eating. The results suggest that a low-fat diet would be beneficial in the treatment of obesity, especially if subjects have a restrained type of eating behaviour

Daily physical activity assessment in free-living subjects : comparison between movement registration and doubly labeled water

The use of movement registration for daily physical activity assessment was evaluated during a 7-day period in 30 free-living subjects. Body movement was registered with a Tracmor motion sensor consisting of a triaxial accelerometer and a data unit for on-line processing of accelerometer output over 1-min intervals. Average Tracmor output was correlated against four different energy estimates: 1) average daily metabolic rate (ADMR), determined with doubly labeled water; 2) ADMR-sleeping metabolic rate (SMR; determined in a respiration chamber); 3) (ADMR-SMR) per kilogram of body mass; and 4) the overall physical activity level (PAL = ADMR/SMR). The highest correlation was found for the relationship between Tracmor output and PAL (r = 0.58). After correction for Tracmor values arising from vibrations produced by transportation means, this correlation was improved to 0.73. There was no difference between Tracmor output and PAL in discriminating between overall activity levels with "low" (PAL &lt;1.60), "moderate" (1.60 &lt;or = PAL &lt;or = 1.85), and "high" (PAL &gt; 1.85) intensity. It is concluded that the Tracmor can be used in free-living subjects to distinguish among interindividual as well as intraindividual levels of daily physical activity

mug up

mug up nHad a mug up at the Skipper's house, after which he and one of his men took me in their punt and rowed me up to the head of the Arm.DNE-citGMS Jan 76Used I and SupUsed I and SupUsed

Dietary fat and body fat: an intervention study.

Dietary fat and body fat: an intervention study. Westerterp KR, Verboeket-van de Venne WP, Westerterp-Plantenga MS, Velthuis-te Wierik EJ, de Graaf C, Weststrate JA. Department of Human Biology, University of Limburg, Maastricht, The Netherlands. OBJECTIVE: Assessment of body composition in relation to the habitual diet and after a six month dietary intervention. DESIGN: After a baseline measurement subjects were randomly assigned to either a group consuming reduced-fat products or a group consuming full-fat products for six months. SUBJECTS: 108 women and 109 men, equally distributed over the age range 19-35 with BMI between 21 and 28, and the age range 36-55 with BMI between 24 and 30. MEASUREMENTS: Food intake was measured by three day dietary record, body composition by deuterium dilution. RESULTS: At baseline, explained variance of %body fat on age and fat-carbohydrate ratio in the diet together were 17% (P < 0.0001) and 36% (P < 0.0001) for women and men, respectively, and on diet alone 7-8% (P < 0.01) independent of gender. The diet intervention caused on average a change in fat intake and body fat mass in subjects of the reduced-fat group of -5 +/- 29 g/d (P < 0.05) and -0.1 +/- 2.1 kg (ns), respectively, and of +23 +/- 31 g/d (P < 0.0001) and +0.5 +/- 2.3 kg (P < 0.05) in subjects of the full-fat group. The change in the fat content of the diet was positively related to a change in energy intake (fat-carbohydrate ratio: R2 = 0.15, P < 0.0001; g fat: R2 = 0.70, P < 0.0001), the latter explaining 5% of the variation in the change in body fat mass (P < 0.001). Subjects changing the fat content of the diet showed a consequent change in body fat mass only when energy intake changed as well. CONCLUSION: The fat content of the diet has an effect on body fat as a function of the effect of dietary fat on energy intake. Publication Types: Clinical Trial Randomized Controlled Tria