An observational study in Obesity Prevention and Healthy, sponsored by University of Leipzig. Recruiting at 1 site in Germany. Open to participants aged 18 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-09-14.
Sponsored by University of Leipzig · Observational
The energy that the human body burns and the amount of food consumed determine a person's body weight. If food intake covers the amount of energy burned, body weight remains constant - a state known as energy balance. Achieving an energy balance is not easy in everyday life. This is reflected in the increasing number of people suffering from morbid obesity. To counteract this development, it is important to have a better understanding of how much food a person should eat.
In this study, the investigators will investigate the amount of food needed to meet a person's energy needs and bring them into energy balance.
Primary aims of the study are i) to technically and biologically validate two whole-room indirect calorimeters (WRICs) and ii) by using whole-room indirect calorimetry, to achieve a more accurate estimate of a person's emergy balance compared to common approximation formulas.
Secondary study aims:
Technical Validation: Six 24-hour methanol burns within each of the two WRICs will be conducted for technical validation.
Biological Validation and Energy Balance Component:
After providing informed consent and meeting inclusion/exclusion criteria, study participants will follow a weight-maintaining diet before their first 24-hour stay in a WRIC (Day 4). During this stay, energy expenditure will be measured under conditions of estimated energy balance. As a measure of energy expnediture relative to energy intake, energy balance will be estimated based on resting energy expenditure, an estimated physical activity level, and an approximation formula applied during the screening procedure.
A second 24-hour stay in the WRIC (Day 6), also under conditions of estimated energy balance, will serve for biological validation. After following the weight-maintaining diet for three additional days, a third 24-hour WRIC stay (Day 10) will assess the achievement of near-perfect energy balance. On the day following this stay (Day 11), participants will have access to a buffet and will be allowed to eat ad libitum.
Subsequently, a 3-day run-in period under weight-maintenance conditions will precede reassessment of 24-hour energy expenditure during increased physical activity in the WRIC (Days 15 and 17). Energy expenditure during energy balance will again be compared to ad libitum food intake at a buffet (Day 18).
Follow-up weight measurements will be conducted one year after study completion to evaluate the influence of achieving near-perfect energy balance-or deviations from it-on weight change. Additionally, fasting blood samples will be collected before and after each WRIC stay, as well as before and after ad libitum food intake, to measure hormones related to appetite control and satiety.
Sample size was calculated assuming a detectable mean difference in energy balance of 100 kcal, a standard deviation of 200 kcal, a two-sided α=0.05, and statistical power ≥80%, resulting in an analytical target sample size of 34 study completers. To account for an anticipated dropout rate of approximately 30%, 49 participants will be enrolled. However, interim analysis after n = 8 subjects will be conducted to adjust needed sample size to variability as detected using here implied methods of indirect calorimetry.
The statistical evaluation with regard to i) technical validation, ii) biological validation, and iii) testing the achievability of an energy balance and its effect on energy consumption are carried out using parametric and non-parametric tests. Data are given as mean value with standard deviation. The significance level is P \< 0.05.
231 studies on the registry are indexed under Body Weight Changes; 30 are open to participants now.
This study's planned enrollment of 49 is below the median of 180 across 45 observational studies indexed under Body Weight Changes.
Browse Body Weight Changes studies →University of Leipzig is the lead sponsor of 148 studies on the registry; 25 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Healthy, non-obese subjects of both sexes.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Healthy subjects of both sexes meeting inclusion criteria.
Energy balance derived from diet-prescribed energy intake and whole-room indirect calorimeter-measured 24-hour energy expenditure
Energy balance is calculated as diet-prescribed energy intake minus 24-hour energy expenditure measured by whole-room indirect calorimetry. Energy expenditure and energy intake are assessed repeatedly under low- and high-energy-turnover conditions. The primary analysis compares energy balance during the diet-specified weight-maintaining diet condition with energy balance after adjustment of energy intake to WRIC-measured 24-hour energy expenditure.
Time frame: From enrollement to the end of 5th stay within the whole-room indirect calorimeter, study day 18.
Coefficient of variation
Technical and biological validation via repeated assessment of methanol combustion as well as repeated stays within the whole-room indirect calorimeters. Measures: recovery, accuracy, macronutrient oxidation rates, respiratory exchange ratio, energy expenditure measures.
Time frame: Prior to enrollement of subjects (technical validation). From enrollement to the end of second stay within the whole-room indirect calorimeter, study day 7.
Energy expenditure
Compared to common approximation formulas, achieving near perfect energy balance using a WRIC has an influence on energy expenditure measures (i.e. 24-hour energy expenditure, sleeping energy expenditure, diet-induced thermogenesis/awake-and-fed thermogenesis, physical exercise energy expenditure)
Time frame: From enrollement to the end of 5th stay within the whole-room indirect calorimeter, study day 11.
Physical exercise expenditure
Compared to common approximation formulas, achieving near perfect energy balance using a WRIC has an influence on energy expenditure measures in the setting of increased physical activity (i.e. 24-hour energy expenditure, sleeping energy expenditure, diet-induced thermogenesis/awake-and-fed thermogenesis, physical exercise energy expenditure)
Time frame: From enrollement to the end of 5th stay within the whole-room indirect calorimeter, study day 18.
Concentrations of hormones involved in energy intake
(Deviation from) near perfect energy balance relates to ad libitum energy intake and changes in hormones implied in appetite control/satiety. Outcome measures: ad libitum food intake during buffet, Leptin, Ghrelin, thyroid hormones, Cortisol, Insulin, IGF-1, Adiponectin, FGF21)
Time frame: From enrollement to the end of 5th stay within the whole-room indirect calorimeter, study day 18.
Body weight change
(Deviation from) near perfect energy balance relates to body weight change.
Time frame: From enrollement to the end of 5th stay within the whole-room indirect calorimeter, study day 18. Body weight change follow-up one year after completion of the study.
Plan to share: No — The decision not to share IPD is based on considerations of participant privacy and data protection. Although all data are anonymized, the sensitive nature of the information collected in this study necessitates careful handling to minimize any risk of identification. Furthermore, the informed consent provided by participants does not explicitly include provisions for data sharing beyond the current study. To ensure compliance with ethical guidelines and data protection regulations, the study team has decided not to make IPD available publicly or to external researchers. However, summary data and study findings will be shared through peer-reviewed publications, ensuring transparency and the opportunity for scientific discourse.
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