Energy Expenditure and Substrate Oxidation in a Whole Room Calorimeter

USDA, Western Human Nutrition Research Center7 enrolled

Overview

The investigators aim to establish a protocol for metabolic rate measurements obtained using continuous monitoring of oxygen consumption and carbon dioxide production in a whole room calorimeter setting.

The purpose of this study is to determine the duration and time course of the thermic effect of single meals consumed by subjects who have been previously fasting for 12 hours overnight. Capturing the full thermic effect of a meal may take up to 8 hours, depending on the calorie load, nutrient composition of the meal, and rate of digestion. The investigators will test meals consisting of conventional foods that are low (20% of energy), moderate (40% of energy) or high (60% of energy) in fat calories, as fat is thought to slow the digestive process. The investigators will test a liquid meal, that is high (60% of energy) in fat calories, as liquid foods are thought to move more quickly through the digestive process. Another purpose of this study is to determine the test-retest reproducibility for the meals described above. To accomplish reproducibility, a volunteer will be permitted to repeat a test day two times using the same test meal.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

SINGLE

Enrollment

Conditions

Overweight Obesity Body Weight

Interventions

Low fat mealOTHER

Meal consisting of conventional foods that is low (20% of energy) in fat calories.

Moderate fat mealOTHER

Meal consisting of conventional foods that is moderate (40% of energy) in fat calories.

High fat mealOTHER

Meal consisting of conventional foods that is high (60% of energy) in fat calories.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Body Mass Index 18.5 - 39.9 kg/m2 Exclusion Criteria: * BMI \< 18.5 or \> 40 kg/m2 * Presence of untreated or uncontrolled metabolic diseases * Presence of gastrointestinal distress or disorders that prevent consumption of a study meal (in particular, the high fat meals) * Presence of Crohn's disease, irritable bowel syndrome, or colitis * Previous gallbladder removal * Presence of cancer or other serious chronic disease * Implanted medical device that is battery operated, such as a pacemaker, defibrillator, electrocardiograph, or nerve simulator * Presence of a large amount of metal in the body such as a hip implant * Current use of tobacco in any form * Claustrophobia * Dietary restrictions that would interfere with consuming study meals * Pregnant or nursing within the last 6 months, or plan to become pregnant

Locations (1)

USDA, ARS, Western Human Nutrition Research Center

Davis, California, United States

Outcomes

Primary Outcomes

Baseline level and change in rate of oxygen consumption

Oxygen consumption rate (VO2/min) measured by gas analyzer while inside whole room calorimeter

Time frame: Measured continuously from baseline up to 600 minutes post-meal

Baseline level and change in rate of carbon dioxide production

Carbon dioxide production rate (VCO2/min) measured by gas analyzer while inside whole room calorimeter

Time frame: Measured continuously from baseline up to 600 minutes post-meal

Baseline level and change in respiratory exchange ratio (RER)

RER is expressed as the ratio of VCO2 to VO2

Time frame: Measured continuously from baseline up to 600 minutes post-meal

Baseline level and change in urinary nitrogen excretion

Urinary nitrogen measured via combustion and gas analysis in mg

Time frame: Measured from discrete specimens and a pooled urine sample collected up to 600 minutes post-meal while in the room calorimeter

Secondary Outcomes

Body weight

measured in kg

Time frame: Baseline

Body fat

Measured in kg using multi frequency bioimpedance

Time frame: Baseline

Lean body mass

Measured in kg using multi frequency bioimpedance

Time frame: Baseline

Total body water

Measured in kg using multi frequency bioimpedance

Data from ClinicalTrials.gov

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Liquid meal that is high (60% of energy) in fat calories.

Time frame: Baseline

Waist circumference

measured in cm

Time frame: Baseline

Hip circumference

measured in cm

Time frame: Baseline

Blood pressure

Both systolic and diastolic pressure measured in mmHg using automated instrument

Time frame: Baseline

Heart rate

measured in beats per minute using automated instrument

Time frame: Baseline

Body temperature

measured in centigrade

Time frame: Baseline

General health and well-being

The SF-36 Short form general health and well-being questionnaire measured once. The survey has eight scales; physical functioning, role limitations due to physical health, role limitations due to emotional problems, energy/fatigue, emotional well-being, social functioning, pain, general health. All 36 items are scored so that a high score defines a more favorable health state. Each item is scored on a 0 to 100 range so that the lowest and highest possible scores are 0 and 100, respectively. Items in the same scale are averaged together to create the 8 scale scores.

Time frame: Baseline

Usual physical activity

Physical activity estimated from the Stanford Brief Physical Activity questionnaire. Scale is categorical for two subscales: work physical activity and leisure time activity.

Time frame: Baseline

Baseline level and change in satiety

Self-reported feelings of fullness measured on a visual analog scale. Responses will be a marked on an unsegmented line from 0 or "not at all" to 100 or "extremely."

Time frame: Baseline, and 5, 10, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 360, 390, 420, 450, and 480 minutes after meal

Baseline level and change in hunger

Self-reported feelings of hunger measured on a visual analog scale. Responses will be a marked on an unsegmented line from 0 or "not at all" to 100 or "extremely."

Time frame: Baseline, and 5, 10, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 360, 390, 420, 450, and 480 minutes after meal

Baseline level and change in desire to eat

Self-reported feelings of the desire to eat measured on a visual analog scale. Responses will be a marked on an unsegmented line from 0 or "not at all" to 100 or "extremely."

Time frame: Baseline, and 5, 10, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 360, 390, 420, 450, and 480 minutes after meal

Baseline level and change in prospective consumption

Self-reported feelings of prospective consumption measured on a visual analog scale. Responses will be a marked on an unsegmented line from 0 or "not at all" to 100 or "extremely."

Time frame: Baseline, and 5, 10, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 360, 390, 420, 450, and 480 minutes after meal

Baseline level and change in energy expenditure

Calculated as kcal/min from oxygen consumption and carbon dioxide production (L/min) and urinary nitrogen excretion (g/min)