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Biomedical subjects

K R Westerterp

Publications and source records attributed to K R Westerterp.

At least 55 records · Page 3Linked to original sources
PubMed2000

Energy, substrate and protein metabolism in morbid obesity before, during and after massive weight loss.

OBJECTIVE: To investigate the effect of surgically induced weight loss on energy, substrate and protein metabolism of morbidly obese patients. DESIGN: A prospective, clinical intervention study of morbidly obese patients before and after surgical treatment. SUBJECTS: Eight morbidly obese patients (BMI 47.88+/-7.03). METHODS: Total energy expenditure (TEE; doubly labeled water method), sleeping metabolic rate (SMR; respiration chamber), body composition (deuterium oxide component of doubly labeled water), substrate metabolism (48 h dietary records, 48 h urine collection and gaseous exchange in the respiration chamber) and whole body protein turnover (primed-continuous infusion of L-[1-13C]-leucine) were measured before, 3 and 12 months after vertical banded gastroplasty (VBG). RESULTS: The TEE decreased as a result of a decreased SMR (64%) and non-SMR (36%; P=0.001). SMR as a function of fat-free mass (FFM) decreased after weight loss (P<0.05). The physical activity index (PAI), defined as TEE/SMR, was low and was not influenced by weight loss. Protein and carbohydrate oxidation decreased significantly after VBG (P<0.05), although 3 months after VBG protein oxidation did not decrease enough to prevent loss of FFM. The energy used for protein turnover was approximately 24% of SMR and did not change after weight loss. CONCLUSIONS: Compensatory processes that oppose weight loss of morbidly obese patients exist, as demonstrated by the disproportional reduction of SMR, and a low PAI. Protein turnover is not a major contributor to the disproportional reduction of SMR.

Adenosine Triphosphate↗
PubMed2000

Effect of exercise training on physical activity and substrate utilization in the elderly.

This study examined the effect of training on physical activity and substrate utilization in the elderly. Before the start, in week 6 and week 12 (T0, T6 and T12) data on physical fitness, physical activity and substrate utilization were collected in the exercise (11 males, 11 females; 63 +/- 8yrs) and control group (6 males, 5 females; 59 +/- 4yrs). Physical activity was registered with a tri-axial accelerometer and substrate utilization was calculated from resting respiratory exchange ratio (RER) by indirect calorimetry. At T6 physical activity on training days was significantly higher than on non-training days (33.4 +/- 10.3 vs. 26.5 +/- 7.8 counts x min(-1); p<0.001). At T12, after adjusting for training activity, physical activity on training days was significantly lower than on non-training days (23.7 +/- 8.4 vs. 28.2 +/- 9.3 counts x min(-1); p<0.01). RER decreased significantly (0.02 +/- 0.03; p <0.05), indicating a relatively larger fat oxidation. Changes in RER were negatively correlated with pre-training RER. In conclusion, in elderly an increase in structured training (exercise) is compensated for by a corresponding decrease in non-training physical activity. Training increased relative fat utilization in elderly with a high pre-training RER, whereas elderly with a low pre-training RER decreased their relative fat utilization.

Aged↗
PubMed2000

Undereating and underrecording of habitual food intake in obese men: selective underreporting of fat intake.

BACKGROUND: Underreporting of food intake is common in obese subjects. OBJECTIVE: One aim of this study was to assess to what extent underreporting by obese men is explained by underrecording (failure to record in a food diary everything that is consumed) or undereating. Another aim of the study was to find out whether there was an indication for selective underreporting. DESIGN: Subjects were 30 obese men with a mean (+/-SD) body mass index (in kg/m(2)) of 34 +/- 4. Total food intake was measured over 1 wk. Energy expenditure (EE) was measured with the doubly labeled water method, and water loss was estimated with deuterium-labeled water. Energy balance was checked for by measuring body weight at the start and end of the food-recording week and 1 wk after the recording week. RESULTS: Mean energy intake and EE were 10.4 +/- 2.5 and 16.7 +/- 2. 4 MJ/d, respectively; underreporting was 37 +/- 16%. The mean body mass loss of 1.0 +/- 1.3 kg over the recording week was significantly different (P < 0.05) from the change in body mass over the nonrecording week, and indicated 26% undereating. Water intake (reported + metabolic water) and water loss were significantly different from each other and indicated 12% underrecording. The reported percentage of energy from fat was a function of the level of underreporting: percentage of energy from fat = 46 - 0.2 x percentage of underreporting (r(2) = 0.28, P = 0.003). CONCLUSIONS: Total underreporting by the obese men was explained by underrecording and undereating. The obese men selectively underreported fat intake.

Adult↗
PubMed2000

Energy expenditure at rest and during sleep in children with Prader-Willi syndrome is explained by body composition.

BACKGROUND: Obesity in Prader-Willi syndrome (PWS) seems to be related to a low basal metabolic rate (BMR). In addition, abnormal sleep patterns reported in PWS might affect sleeping metabolic rate (SMR). OBJECTIVE: Our objective was to assess BMR and SMR adjusted for fat-free mass in young PWS patients. DESIGN: Subjects were 17 PWS patients (10 females and 7 males aged 7.5-19.8 y) and 17 obese control subjects matched for sex and bone age. SMR was measured in a respiratory chamber, BMR with a ventilated-hood system, and body composition by deuterium dilution. RESULTS: BMR and SMR were significantly lower in the PWS group than in the control group (5.36 +/- 1.18 and 4.62 +/- 1.08 MJ/d compared with 6.38 +/- 1.55 and 5.60 +/- 1.52 MJ/d, respectively; P < 0.05). When fat-free mass was included in the analysis, multiple regression showed no differences in BMR and SMR between groups. When weight was included in the analysis instead of fat-free mass, SMR was lower in the PWS group. Fat-free mass was lower in the PWS group both as an absolute value and when adjusted for height. CONCLUSION: BMR and SMR are low in young patients with PWS because of a low fat-free mass.

Adolescent↗
PubMed2000

Daily physical activity and ageing.

A typical aspect of aging is the increase in variability of a feature within a population, suggesting individual variation in the decline with age. The decline is probably inevitable (predisposed), but some show slower declines than others. Physical activity might be one of the avenues to influence the aging process. There is still a need for validated techniques of estimating habitual physical activity to study the relationship between physical activity and health. Doubly labeled water studies show a decrease in the average proportion of daily energy expenditure for physical activity of about 35% at the age of 20 to 25% at the age of 90. In absolute figures, the activity-induced energy expenditure falls to one third of the initial value over the corresponding age interval. Exercise training does not seem to prevent the age-associated decline in physical activity because of compensation by a decrease in non-training physical activity, in contrast to younger age groups. The effects of the habitual activity level and of exercise on the age-related decline in muscle mass are small if present at all. There is, however, a clear-cut effect of habitual activity and exercise training on muscle function. The positive effects are reflected in muscle fiber type, capillary density, and aerobic capacity. Physical inactivity is an important determinant of disability and mortality risk. Even a recent increase in activity level can have an important effect, although the benefits are also easily lost when the activity level is again reduced.

Activities of Daily Living↗
PubMed2000

Effects of discontinuation of growth hormone treatment on body composition and metabolism.

This study was directed to the investigation of two different aspects of growth hormone: What are the metabolic consequences following the discontinuation of treatment and are these metabolic effects correlated with the growth-promoting effects seen in the first year of treatment? The study was performed on 12 growth hormone-deficient (GHD) patients who reached their final height. Each patient was matched with a non-GHD person of the same sex and about the same age. Immediately after the discontinuation of treatment, and 6 weeks and 6 months later, the following anthropometric variables were assessed: height, weight, skinfold thicknesses (biceps, triceps, subscapular and suprailiacal), body volume (underwater weighing) and total body water (deuterium dilution). To describe energy metabolism, basal metabolic rate assessed by ventilated hood, and sleep metabolic rate assessed by respiration chamber, were studied. Body composition was calculated from weight, volume and total body water. Clear metabolic effects were found after the discontinuation of treatment in GHD children: there was a decrease in fat free mass and sleep metabolic rate. Also, a strong correlation between the above-mentioned effects and the growth-promoting effects of human growth hormone at the beginning of the treatment was observed. The fact that this correlation exists poses the interesting question of whether the results from a test treatment lasting some weeks could be used to predict the long-term effects of hGH.

Adolescent↗
PubMed2000

Increase in fat oxidation on a high-fat diet is accompanied by an increase in triglyceride-derived fatty acid oxidation.

The aim of this study is to investigate the mechanism behind the slow increase in fat oxidation on a high-fat diet. Therefore, we determined 24-h substrate oxidation using respiration chambers and the rate of appearance and oxidation of plasma-derived fatty acids in seven healthy nonobese men (age 23 +/- 2 years, height 1.85 +/- 0.03 m, weight 70.4 +/- 2.3 kg, % body fat 13 +/- 1). Before testing, they consumed a low-fat diet (30% fat, 55% carbohydrate) at home for 3 days. Measurements were performed after 1 day consumption of either a low-fat diet (LF), a high-fat diet (HF1, 60% fat, 25% carbohydrate), or a high-fat diet preceded by a glycogen-lowering exercise test (HF1+EX), and after 7 days on a high-fat diet (HF7). After an overnight fast, an infusion of [U-13C]palmitate (0.00806 micromol x min(-1) x kg(-1)) was started and continued for 2 h at rest followed by 1 h of exercise at 50% of maximal power output (Wmax). Whole-body fat oxidation was measured using indirect calorimetry, and plasma-derived fatty acid oxidation was evaluated by measuring breath 13CO2 enrichment and corrected with the acetate recovery factor. Twenty-four-hour fat oxidation gradually increased on the high-fat diet. Both at rest and during exercise, there was no change in rate of appearance of fatty acids and plasma-derived fatty acid oxidation. Triglyceride-derived fatty acid oxidation tended to be higher after 7 days of high-fat diet at rest (P < 0.07). This difference was significant during exercise (P < 0.05). In conclusion, the results from this study suggest that triglyceride-derived fatty acid oxidation (VLDL or intramuscular triglycerides) plays a role in the increase in fat oxidation on a high-fat diet, but plasma-derived fatty acids remain the major source for fat oxidation.

Adult↗
PubMed2000

Improved reporting of habitual food intake after confrontation with earlier results on food reporting.

The aim of the present study was to improve the reporting of food intake by confronting subjects with their way of reporting food intake, e.g. under-recording and/or under-eating. To minimize portion size errors, eighteen female dietitians were recruited as subjects. Energy- and water intake were measured for 1 week with a weighed dietary record. Resting metabolic rate was measured with an open-circuit ventilated-hood indirect calorimeter, and physical activity was measured with an accelerometer for movement registration. Water loss was estimated with 2H-labelled water. Energy balance was checked for by measuring empty body-weight 1 week before the start, at the start and at the end of the recording week. In the first part of the study, the change in body weight in the non-recording week was 0.14 kg and in the recording week -0.45 kg (P 0.02), indicating 12% under-eating. Total water intake closely matched measured water loss, indicating a high recording precision. There was under-reporting of habitual food intake that could be fully explained by under-eating. In the second part of the study, subjects were confronted with these results and the protocol was repeated. This time there was no significant change in body weight in the recording week, indicating no under-eating. The reporting of habitual food intake had been improved. In conclusion, in the studied group of highly motivated lean women, under-reporting of habitual food intake (here due to under-eating) could be eliminated by confrontation with the results of this phenomenon.

Adult↗
PubMed2000

Resting energy expenditure, activity energy expenditure and total energy expenditure at age 91-96 years.

There is a limited knowledge concerning energy requirements of the elderly, especially the oldest old (> 80 years). Energy requirements should be estimated from measurements of energy expenditure. For this purpose twenty-one free-living individuals (eight males, thirteen females) aged 91-96 years living in Göteborg, Sweden were studied. Total body water (TBW) measured by the doubly-labelled-water (DLW) technique was 29.5 (sd 5.4) kg in females and 35.6 (sd 4.3) kg in males. TBW measured using bioelectric impedance (BIA) was 31.6 (sd 6.4) kg in females and 42.0 (sd 7.4) kg in males. The mean difference between TBW measured by BIA and that measured by DLW was 3.54 (sd 3.6) kg (P = 0.0002). Resting metabolic rate (RMR) was measured using a ventilated-hood system and averaged 5.36 (sd 0.71) MJ/d in females (n 12) and 6.09 (sd 0.91) MJ/d in males (n 8). Difference between measured RMR and predicted BMR (n 20) was 0.015 (sd 0.86) MJ/d (NS). Total energy expenditure (TEE) measured by DLW averaged 6.3 (sd 0.81) MJ/d in females and 8.1 (sd 0.73) MJ/d in males. Activity energy expenditure (TEE - RMR), thus including diet-induced thermogenesis (DIT), averaged 0.95 (sd 0.95) MJ/d in females (n 12) and 2.02 (sd 1.13) MJ/d in males. Physical activity level (TEE/BMR) averaged 1.19 (sd 0. 19) in females and 1.36 (sd 0.21) (P = 0.08) in males. If DIT is assumed to be 10 % of the TEE, energy spent on physical activity will be very low in this population.

Aged↗
PubMed2000

Daily physical activity, aging and body composition.

Increasing age is associated with changes in physical activity and loss of fat-free mass. The question is whether an active life style can delay the progressive loss of fat-free mass and functional capacity. A review of available evidence from doubly labeled water studies showed that there is no association between fat-free mass and the level of physical activity in subjects over 60. Physical activity does not seem to affect the age-induced loss of fat-free mass. However, an active life style has positive effects on muscle function and thus is an important determinant of independent living at old age.

Aged↗
PubMed1999

Effect of exercise training on total daily physical activity in elderly humans.

This study examined the effect of 12 weeks of exercise training on daily physical activity in elderly humans. Training consisted of a weekly group session and an individual session with cardio- and weight-stack machines. A group of 15 subjects served as the exercise group [EXER mean age 59 (SD 4) years], and 7 subjects as the controls [CONT mean age 57 (SD 3) years]. Physical activity and physical fitness were measured before the start of training (T), at week 6 and week 12 (T0, T6, T12 respectively) in EXER, and at T0 and T12 in CONT. Physical activity over 14 days was measured using a tri-axial accelerometer and physical fitness was measured during an incremental exercise test. At T12, mean maximal power output had significantly increased in EXER compared to CONT 8 (SD 12) vs -5 (SD 9) W; P < 0.02] and mean submaximal heart rate (at 100 W) had reduced [-10 (SD 7) vs -2 (SD 6) beats x min(-1); P < 0.05]. No differences or changes in physical activity were observed between EXER and CONT. At T6, physical activity on training days was significantly higher than on non-training days (P < 0.001). When the accelerometer output of the training session was subtracted from the accelerometer output on training days, at T12 non-training physical activity was significantly lower than on non-training days (P < 0.004). Accelerometer output of the individual training session at T12 had significantly increased compared to T6 (P < 0.05), whereas, accelerometer output of the group training session had remained unchanged. In conclusion, in elderly subjects an exercise training programme of moderate intensity resulted in an improved physical fitness but had no effect on total daily physical activity. Training activity was compensated for by a decrease in non-training physical activity.

Acceleration↗
PubMed1999

Skinfold measurements in children with cystic fibrosis: monitoring fat-free mass and exercise effects.

UNLABELLED: Monitoring fat free mass (FFM), an indicator of nutritional status and a predictor of exercise performance in children, is particularly important in patients with cystic fibrosis (CF). We assessed validity of the skinfold method for measuring FFM, and its changes with exercise training, in children with CF. A total of 14 children with moderately severe symptoms of CF (age 10-18 years) were followed longitudinally and measured three times, before (at 0 and 6 months) and after exercise training (at 12 months). Separately, single measurements were conducted in 12 children with mild symptoms of CF and in 13 healthy controls. FFM was calculated from four skinfold measurements, and compared with estimations from total body water measured with deuterium dilution. The FFM calculated from skinfolds was 1.7% (P < 0.05) and 3.3% (P < 0.005) higher than that estimated with deuterium oxide dilution in patients with CF and controls, respectively. Limits of agreement were similar in patients with moderate and mild symptoms and in controls. The measurements in patients with moderate symptoms showed similar bias and limits of agreement at 6 and 12 months as compared to 0 months. Changes in FFM measured with both methods were significantly correlated before exercise (r = 0.82, P < 0.0005), and after exercise training (r = 0. 60, P < 0.05). CONCLUSION: In children with cystic fibrosis, skinfold measurements are applicable to monitor fat free mass irrespective of clinical severity of the disease, and repeated measurements at intervals of 6 months are applicable to monitor changes in fat free mass during exercise training.

Adolescent↗
PubMed1999

Bioelectrical impedance analysis to assess changes in total body water in patients with cancer.

Predominantly based on studies in obese individuals, the applicability of single-frequency bioelectrical impedance analysis (BIA) to measure changes in total body water and fat-free mass has been questioned. To further clarify this issue, we compared changes in BIA-derived height(2)/resistance (ht(2)/R) with changes in total body water (deuterium dilution, delta-TBWdeu) in cancer patients participating in a clinical trial. Thirty-three patients (mean body mass index 23.2 +/- 3.5 kg/m(2)) were studied after an average follow-up of 11 weeks. Changes in TBWdeu occurred in both directions (mean +0.2 +/- 1.6 L, range -3.3 to +3.1 L). These changes were significantly predicted by changes in ht(2)/R (r(2)0.43, P < 0.0001, SEE 1.22 L), although precision was poor (residual SD 1. 2 L). There were in this regard no significant differences between patients with and without underweight. We conclude that in underweight and normal-weight cancer patients, BIA-derived changes in ht(2)/R significantly predict changes in total body water assessed by deuterium dilution.

Adipose Tissue↗
PubMed1999

Body composition, water turnover and energy turnover assessment with labelled water.

Our understanding of human energy metabolism has benefited greatly from the application of water labelled with 2H and 18O for the measurement of total body water, water turnover and total daily energy expenditure. Applications include validation of techniques for the assessment of dietary intake and physical activity, assessment of water and energy requirement and the assessment of the effect of dietary and physical activity interventions, including its use with endurance athletes competing at the highest level. Critical aspects of the application are isotope dose preparation, sample collection, sample analysis and the calculation procedure. The labelled-water method can easily be applied in normal living conditions, including exercise, and in the clinical setting. However, sample analysis requires a sophisticated laboratory with an isotope-ratio mass spectrometer and a sample preparation system. Examples of insights based on labelled-water studies are: (1) self-reported dietary intakes often underestimate energy requirements; (2) subjects have problems maintaining energy balance when daily energy expenditure exceeds 2.5 times resting energy expenditure. Devices for the assessment of physical activity validated using labelled water allow the study of activity patterns and strategies to influence the activity level of a sedentary society.

Body Composition↗
PubMed1999

Satiety related to 24 h diet-induced thermogenesis during high protein/carbohydrate vs high fat diets measured in a respiration chamber.

OBJECTIVE: Assessment of a possible relationship between perception of satiety and diet-induced thermogenesis, with different macronutrient compositions, in a controlled situation over 24 h. DESIGN: Two diets with different macronutrient compositions were offered to all subjects in randomized order. SETTING: The study was executed in the respiration chambers at the department of Human Biology, Maastricht University. SUBJECTS: Subjects were eight females, ages 23-33 y, BMI 23+/-3 kg/m2, recruited from University staff and students. INTERVENTIONS: Subjects were fed in energy balance, with protein/carbohydrate/fat: 29/61/10 and 9/30/61 percentage of energy, with fixed meal sizes and meal intervals, and a fixed activity protocol, during 36 h experiments in a respiration chamber. The appetite profile was assessed by questionnaires during the day and during meals. Diet induced thermogenesis was determined as part of the energy expenditure. RESULTS: Energy balance was almost complete, with non-significant deviations. Diet-Induced-Thermogenesis (DIT) was 14.6+/-2.9%, on the high protein/carbohydrate diet, and 10.5+/-3.8% on the high fat diet (P < 0.01). With the high protein/high carbohydrate diet, satiety was higher during meals (P < 0.001; P < 0.05), as well as over 24 h (P < 0.001), than with the high fat diet. Within one diet, 24 h DIT and satiety were correlated (r = 0.6; P < 0.05). The difference in DIT between the diets correlated with the differences in satiety (r = 0.8; P < 0.01). CONCLUSION: In lean women, satiety and DIT were synchronously higher with a high protein/high carbohydrate diet than with a high fat diet. Differences (due to the different macronutrient compositions) in DIT correlated with differences in satiety over 24 h.

Adult↗
PubMed1999

Obesity and physical activity.

OBJECTIVES: Three aspects of obesity and physical activity are reviewed: whether the obese are inactive; how the activity level can be increased; and which are the effects of an increase in physical activity in combination with a reduction of energy intake. METHOD: The focus is on an objective approach that is, activity associated energy expenditure as measured with doubly labelled water. RESULTS: Activity associated energy expenditure increases with body mass index while the average physical activity level does not change. The majority of obese subjects is moderately active. An increase in the activity level of obese subjects is limited by the ability to perform exercise of higher intensity. Training programs obese subjects can cope with are until now not rewarded by weight loss. A possible loss in fat mass is compensated by a gain in fat-free mass. CONCLUSIONS: Obese subjects can only reach a significant weight loss with an energy restricted diet. Mild energy restriction will already result in very significant weight loss when one complies with the diet. An increase in physical activity is necessary to compensate for the reduction in activity induced energy expenditure and should be facilitated by the lower body mass.

Adult↗
PubMed1999

Diet induced thermogenesis measured over 24h in a respiration chamber: effect of diet composition.

OBJECTIVE: To study the effect of diet composition on diet-induced thermogenesis (DIT) over 24h in a respiration chamber. SUBJECTS: Eight healthy female volunteers (age 27 +/- 3 y; body mass index, BMI 23 +/- 3 kg/m2). DIETS: A high protein and carbohydrate (HP/C) (60:10:30; percentage energy (E%)carbohydrate, fat and protein, respectively) and high fat (HF) (30:60:10 respectively) diet, both isoenergetic, isovolumetric, composed of normal food items and matched for organoleptic properties (taste, smell, appearance). DESIGN: Subjects spent two 36h periods each in a respiration chamber consuming both test diets in random order. Components of 24h energy expenditure (24h EE): sleeping metabolic rate, DIT and activity induced energy expenditure were measured. RESULTS: DIT was higher in all subjects while on the HP/C diet (1295 kJ/d vs 931 kJ/d; 14.6% vs 10.5% of energy intake; P < 0.02). There was no significant difference in other components or total 24h EE, although there was a trend towards higher EE on the HP/C diet. CONCLUSION: A high protein and carbohydrate diet induces a greater thermic response in healthy individuals when compared to a high fat diet.

Adult↗