Dietary macronutrient composition and its effect on 24-h substrate oxidation: A study of diurnal variations in carbohydrate and fat intake.

Background & Aims: In recent times, the complexity of food styles and meal content has increased, leading to significant variations in macronutrient composition between meals. This phenomenon has coincided with a rise in obesity rates. We aimed to determine whether a large variation in macronutrient composition between meals results in reduced fat oxidation.

Effects of energy loads on energy and nutrient absorption rates and gut microbiome in humans: A randomized crossover trial.

Objective: This study aimed to determine the effects of different energy loads on the gut microbiota composition and the rates of energy and nutrient excretion via feces and urine.

Methods: A randomized crossover dietary intervention study was conducted with three dietary conditions: overfeeding (OF), control (CON), and underfeeding (UF). Ten healthy men were subjected to each condition for 8 days (4 days and 3 nights in nonlaboratory and laboratory settings each).

Investigation of seasonality of human spontaneous physical activity and energy expenditure in respiratory chamber in Phoenix, Arizona.

Objective: The existence of seasonal changes in energy metabolism is uncertain. We investigated the relationship between the seasons and spontaneous physical activity (SPA), energy expenditure (EE), and other components measured in a respiratory chamber.

Methods: Between 1985-2005, 671 healthy adults (aged 28.

Effects of Short-term Fasting on Ghrelin/GH/IGF-1 Axis in Healthy Humans: The Role of Ghrelin in the Thrifty Phenotype.

Context: A greater decrease in 24-hour energy expenditure (24hEE) during short-term fasting is indicative of a thrifty phenotype.

Objective: As ghrelin and the growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis are implicated in the regulation of energy intake and metabolism, we investigated whether ghrelin, GH, and IGF-1 concentrations mediate the fasting-induced decrease in 24hEE that characterizes thriftiness.

Methods: In 47 healthy individuals, 24hEE was measured in a whole-room indirect calorimeter both during 24-hour eucaloric and fasting conditions.

Associations between motorized transport access, out-of-home activities, and life-space mobility in older adults in Japan.

Background: Motorized transport access and out-of-home activities are two potential correlates of Life-space mobility (LSM), a common research topic in mobility studies of older adults. These correlates remain mostly unexplored in previous literature and relating them with LSM can reveal directions for improving the LSM of older adults.

Methods: The associations between motorized transport access, out-of-home activities, and LSM were examined using data from 1,333 older adults (mean age = 70.

Trends in spontaneous physical activity and energy expenditure among adults in a respiratory chamber, 1985 to 2005.

Objective: Fidgeting, a type of spontaneous physical activity (SPA), has substantial thermogenic potential. This research aims to examine secular trends in SPA and energy expenditure (EE) inside a respiratory chamber.

Methods: From 1985 to 2005, healthy adults (n = 678; mean age: 28.

BOLD signal response in primary visual cortex to flickering checkerboard increases with stimulus temporal frequency in older adults.

Many older adults have difficulty seeing brief visual stimuli which younger adults can easily recognize. The primary visual cortex (V1) may induce this difficulty. However, in neuroimaging studies, the V1 response change to the increase of temporal frequency of visual stimulus in older adults was unclear.

Eating Dinner Early Improves 24-h Blood Glucose Levels and Boosts Lipid Metabolism after Breakfast the Next Day: A Randomized Cross-Over Trial.

To examine whether mild early time-restricted eating (eating dinner at 18:00 vs. at 21:00) improves 24-h blood glucose levels and postprandial lipid metabolism in healthy adults. Twelve participants (2 males and 10 females) were included in the study.

Reduced adaptive thermogenesis during acute protein-imbalanced overfeeding is a metabolic hallmark of the human thrifty phenotype.

Background: The human thrifty phenotype is characterized by a greater decrease in 24-h energy expenditure (24EE) during fasting due to relatively higher eucaloric 24EE in sedentary conditions, both of which are indicative of greater propensity to weight gain. Thriftiness is also associated with a smaller increase in 24EE (i.e.

Reduced Albumin Concentration Predicts Weight Gain and Higher Energy Intake in Humans.

Objective: Circulating albumin is negatively associated with adiposity but whether it is associated with increased energy intake, lower energy expenditure or weight gain has not been examined.

Methods: In (n=238; 146 men), we evaluated whether fasting albumin concentration was associated with 24-h energy expenditure and energy intake. In (n=325;167 men), we evaluated the association between plasma albumin and change in weight and body composition.

Procedures for Measuring Excreted and Ingested Calories to Assess Nutrient Absorption Using Bomb Calorimetry.

Objective: With the upsurge in interest in the gut microbiome, complete and accurate measurement of ingested calories and calories lost through excreted stool is crucial for assessing the effect of the microbiota on nutrient absorption.

Methods: Measurement of ingested and excreted calories was conducted over 3 days. Meals were made in duplicate: one was given to the participant, and one was used for the measurement of calories.

Early adaptive thermogenesis is a determinant of weight loss after six weeks of caloric restriction in overweight subjects.

Background: Adaptive thermogenesis during prolonged energy deficit refers to the greater than expected reduction in energy expenditure (EE) independent of concomitant loss of metabolically active body mass.

Objective: As inter-individual variability in the magnitude of adaptive thermogenesis may influence the extent of energy deficit thereby predicting the amount of weight reduction, we investigated whether early adaptive thermogenesis is a determinant of weight loss after 6 weeks of daily 50% caloric restriction in an inpatient setting.

Design And Methods: The current study reports the results of an exploratory, secondary analysis in overweight but otherwise healthy subjects (n = 11, 7 men, 35 ± 9y, BMI = 40 ± 7 kg/m, body fat = 63.

Metabolic Responses to 24-Hour Fasting and Mild Cold Exposure in Overweight Individuals Are Correlated and Accompanied by Changes in FGF21 Concentration.

A greater decrease in 24-h energy expenditure (24 EE) during 24-h fasting defines a "thriftier" metabolic phenotype prone to weight gain during overfeeding and resistant to weight loss during caloric restriction. As the thermogenic response to mild cold exposure (COLD) may similarly characterize this human phenotype identified by acute fasting conditions, we analyzed changes in 24 EE and sleeping metabolic rate (SLEEP) in a whole-room indirect calorimeter during 24-h fasting at thermoneutrality (24°C) and during energy balance both at thermoneutrality (24°C) and mild cold (19°C) in 20 healthy volunteers (80% male; aged 36.6 ± 11.

Higher Urinary Dopamine Concentration is Associated with Greater Ad Libitum Energy Intake in Humans.

Objective: This study aimed to assess the relationship between dopamine, a neurotransmitter involved in feeding behavior, and ad libitum energy intake in humans.

Methods: Healthy individuals (n = 158; 72 Native American, 50 white, 18 black, and 18 Hispanic participants; BMI: 33 [SD 9] kg/m ; body fat: 33% [SD 9%]) were admitted for two inpatient studies investigating the determinants of ad libitum energy intake and assessed for 3 days using a highly reproducible, computerized vending machine paradigm. Urine was collected for 24 hours during eucaloric conditions prior to the ad libitum feeding period, and urinary dopamine excretion rate was quantified by high-performance liquid chromatography.

Effects of cognitive and visual loads on driving performance after take-over request (TOR) in automated driving.

The present study investigated effects of cognitive and visual loads on driving performance after take-over request (TOR) in an automated driving task. Participants completed automated driving in a driving simulator without a non-driving related task, with an easy non-driving related task, and with a difficult non-driving related task. The primary task was to monitor the environment and the system state.

Recharacterizing the Metabolic State of Energy Balance in Thrifty and Spendthrift Phenotypes.

Purpose: The human thrifty phenotype hypothesis presupposes that lower 24-hour (24h) energy expenditure (24EE) during famine preserves body mass and promotes survival. The prevailing view defines thrifty individuals as having a lower 24EE during fasting. However, it is also plausible that the greater decline in 24EE during fasting in thrifty individuals is due to higher 24EE during energy balance conditions (ENBAL).

Urinary Norepinephrine Is a Metabolic Determinant of 24-Hour Energy Expenditure and Sleeping Metabolic Rate in Adult Humans.

Background: Interindividual variability in 24-hour energy expenditure (24EE) during energy-balance conditions is mainly determined by differences in body composition and demographic factors. Previous studies suggested that 24EE might also be influenced by sympathetic nervous system activity via catecholamine (norepinephrine, epinephrine) secretion. Therefore, we analyzed the association between catecholamines and energy expenditure in 202 individuals from a heterogeneous population of mixed ethnicities.

Simple Prediction of Metabolic Equivalents of Daily Activities Using Heart Rate Monitor without Calibration of Individuals.

Background: Heart rate (HR) during physical activity is strongly affected by the level of physical fitness. Therefore, to assess the effects of fitness, we developed predictive equations to estimate the metabolic equivalent (MET) of daily activities, which includes low intensity activities, by % HR reserve (%HRR), resting HR, and multiple physical characteristics.

Methods: Forty volunteers between the ages of 21 and 55 performed 20 types of daily activities while recording HR and sampling expired gas to evaluate METs values.

Validity of estimating physical activity intensity using a triaxial accelerometer in healthy adults and older adults.

Background: A triaxial accelerometer with an algorithm that could discriminate locomotive and non-locomotive activities in adults has been developed. However, in the elderly, this accelerometer has not yet been validated. The aim were to examine the validity of this accelerometer in the healthy elderly, and to compare the results with those derived in a healthy younger sample.