Operation Everest III: energy and water balance.

We hypothesized that hypoxia decreases energy intake and increases total energy requirement and, additionally, that decreased barometric pressure increases total water requirement. Energy and water balance was studied over 31 days in a hypobaric chamber at 452-253 Torr (corresponding to 4,500-8,848 m altitude), after 7 days acclimatization at 4,350 m. Subjects were eight men, age 27+/-4 years (mean+/-SD), body mass index 22.

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.

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.

Assessment of physical activity level in relation to obesity: current evidence and research issues.

Purpose: Validations of methods for the assessment of physical activity and studies on the relation between energy expenditure of activity and obesity were reviewed, with suggestions for further research.

Design: Validation studies of field methods for the assessment of physical activity against doubly labeled water were evaluated, studies on the relation between doubly labeled water assessed energy expenditure of activity and obesity are discussed.

Methods: Three field methods for the assessment of physical activity, validated with doubly labeled water as a criterion method, were included: activity questionnaires, heart rate monitoring, and motion sensors.

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).

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.

Doubly labelled water validation of three physical activity questionnaires.

This study investigated the validity of the Baecke Questionnaire, the Five City Project Questionnaire, and the Tecumseh Community Health Study Questionnaire in 19 Flemish males, using correlation and multiple stepwise regression analyses. The three questionnaires are commonly used physical activity questionnaires in epidemiological studies. The physical activity level (PAL) as measured with the doubly labelled water method was used as the criterion.

Appetite at "high altitude" [Operation Everest III (Comex-'97)]: a simulated ascent of Mount Everest.

We hypothesized that progressive loss of body mass during high-altitude sojourns is largely caused by decreased food intake, possibly due to hypobaric hypoxia. Therefore we assessed the effect of long-term hypobaric hypoxia per se on appetite in eight men who were exposed to a 31-day simulated stay at several altitudes up to the peak of Mt. Everest (8,848 m).

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.

Physical activity assessment with accelerometers.

Objective: Evaluation of motion sensors, specifically accelerometers, as an objective tool for the assessment of physical activity in large populations, over periods long enough to be representative of normal daily life and with minimal discomfort to the subjects.

Method: Review of validation studies of accelerometers with indirect calorimetry as a reference method. Accelerometers were commercially available one-axial accelerometers: Caltrac, Computer Science Application (CSA) accelerometer, Mini Motionlogger Actigraph; the tri-axial accelerometer Tritrac-R3 D; and an tri-axial accelerometer for movement registration (Tracmor) from our laboratory.

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].

Underreporting of habitual food intake is explained by undereating in highly motivated lean women.

Underreporting of habitual food intake can be explained by underrecording and/or undereating. This study was designed to discriminate between the two errors mentioned, by measuring energy and water balance. Twenty-four lean female dieticians were recruited as subjects.

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).

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.

Effect of protein source and quantity on protein metabolism in elderly women.

To study sequentially the effect of meal feeding and the effect of protein source and quantity on whole-body protein metabolism, 12 elderly women consumed 3 diets differing in both the quantity and source of protein (diet A: 5.3% of energy intake provided by animal protein and 5.0% by vegetable protein; diet B: 14.

Alterations in energy balance with exercise.

The doubly labeled water method for measuring average daily metabolic rate (ADMR) in combination with resting metabolic rate (RMR) allows one to assess the relation between exercise and energy balance. Three topics were included in an analysis of available data: 1) the limits of energy turnover in relation to physical performance for the achievement of energy balance, 2) the effect of an exercise intervention on daily energy turnover and its components, and 3) the effect of exercise on body composition. In the general population, physical activity level (PAL: ADMR/RMR) ranges between 1.

Assessment of energy expenditure in overweight women.

Purpose: To compare field measures of average daily energy expenditure (ADEE) against criterion data by the doubly labeled water method (DLW) in overweight women.

Methods: The subject were 20 overweight (BMI 29.9 +a- 3.

A comparison of the effect of free access to reduced fat products or their full fat equivalents on food intake, body weight, blood lipids and fat-soluble antioxidants levels and haemostasis variables.

Objectives: To compare the effects of free access to reduced fat products or their full fat equivalents on fat and energy intake, body weight, plasma lipids and fat-soluble antioxidants concentrations and haemostasis variables.

Design: A multicentre open randomised controlled trial in which intervention and control groups were followed in parallel for six months. Volunteers had free access to 44 different foods either in reduced fat or full fat version, covering between 30 and 40% of energy intake.

Are skinfold measurements suitable to compare body fat between children with spastic cerebral palsy and healthy controls?

The aim of this study was to assess whether percentage of body fat (BF) can be predicted adequately from skinfold measurements in comparative studies of children with spastic cerebral palsy (CP) and healthy control children. The deuterium dilution technique (D2O) was used as a reference method. In contrast with what was expected, %BF predicted from skinfold measurements was considerably lower than that determined by the D2O method in children with CP, whereas in the controls this was not seen.

Fat balance in obese subjects: role of glycogen stores.

In a previous study, we showed that lean subjects are capable of rapidly adjusting fat oxidation to fat intake on a high-fat (HF) diet when glycogen stores are lowered by exhaustive exercise. However, it has been proposed that obese subjects have impaired fat oxidation. We therefore studied the effect of low glycogen stores on fat oxidation after a switch from a reduced-fat (RF) diet to an HF diet in obese subjects.

Energy utilization and growth in breast-fed and formula-fed infants measured prospectively during the first year of life.

This study is the first to report approximations of energy requirements for male and female breast-fed and formula-fed infants based on individual estimates of total daily energy expenditure (TDEE) and energy deposition derived from total body fat (TBF) and fat-free mass (FFM) gain as determined by total-body electrical conductivity. In 46 healthy, full-term infants the effect of > or = 4 mo of exclusive breast-feeding compared with formula feeding on macronutrient and energy intake, TDEE, energy deposition, and growth were investigated prospectively. Metabolizable energy intake (MEI) was assessed from macronutrient intake by test weighing (MEI-TW) and from the sum of TDEE and energy deposition (MEI-Pred).

Reduction of sleeping metabolic rate after vertical banded gastroplasty.

Objective: To investigate whether long-term weight loss after vertical banded gastroplasty (VBG) results in a sustained reduction of sleeping metabolic rate (SMR) as a persistent risk factor for weight regain.

Design: Longitudinal clinical intervention study of morbidly obese patients undergoing VBG.

Patients: Group I: Six patients in which body composition and SMR were measured before and at 3, 6 and 12 months after VBG.