Obesity & OverweightNCT07739095
Weight Loss and Hunger
A study testing Exercise and Dietary Intervention in people with Obesity & Overweight, run by University of Ottawa at 1 site in Canada.
Trial summary
Weight loss is difficult and weight maintenance even worse. The principles of dieting dictate that to maintain weight loss, one has to eat less calories than they did before the diet. Read more about this study
- Who is it for?
- Ages 18 to 55 years
- Conditions the study is for
- Obesity & Overweight
- What is being tested?
- Exercise and Dietary Intervention
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 40 participants
- Where
- 1 siteCanada
- Study dates
- 1 Sep 2026to 1 Sep 2028
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 55 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- 18-55 years of age;
- non-smoking;
- obese class I-II (30 kg/m2 ≤ BMI < 40 kg/m2);
- weight stable (± 2 kg during the 6 months prior to enrollment);
- Sedentary (<2 times/week of 30 min of continuous exercise)
- In addition, Females will be included if:
- 1) premenopausal (2 menses in the 3 months preceding testing, no increase in cycle irregularity in the 12 months preceding testing).
Who cannot join
- have a current diagnosis of an axis 1 psychiatric disorder (i.e. mood, anxiety and eating disorders);
- currently use antidepressants, thyroid medication, or any medication that could affect appetite;
- have a history of cardiac problems or symptoms suggestive of any cardiac condition;
- have a current diagnosis or history of diabetes, confirmed by a measure of HbA1c during the screening visit;
- have alcohol intake that exceeds recommendations or alcoholism, or current addictions to opiates, cocaine or stimulants;
- currently taking monoamine oxidase inhibitors, pressor agents, warfarin, anticonvulsants, phenylbutazone, or tricyclic antidepressants;
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- have uncontrolled thyroid disease;
- have any osteoarticular condition, or other reasons that would prevent them from achieving the proposed walking targets.
- In addition, Females will be excluded if they:
- are pregnant or planning to become pregnant over the course of the study;
- are peri- or post-menopausal or have had surgically induced menopause.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Canada1 site
University of Ottawa
Ottawa, Ontario, K1S 5S9
Eric Doucet, PhD, 613-562-5800 ext. 4271, edoucet@uottawa.ca
Noemie Beauregard, PhD (c), 613-857-3960, nbeau029@uottawa.ca
About this study
Official title: Weight Loss and Hunger: Did we Get it Wrong All This Time?
Weight loss is difficult and weight maintenance even worse. The principles of dieting dictate that to maintain weight loss, one has to eat less calories than they did before the diet. However, there is evidence to show that it may be the diet per se and not the weight loss that makes people more hungry and vulnerable to weight regain. This study will explore whether appetite control can be restored to normal levels through an individually tailored increase in calories after weight loss. If supported, the findings from this study could alter the way we view dieting.
Read the detailed description
Weight loss reduces all components of the energy budget, i.e. resting energy expenditure (EE), the thermic effect of feeding and the energy cost of physical activities. The corollary of this observation is that to achieve energy balance at a lowered body weight (if EE is not increased through purposeful physical activity), energy intake (EI) needs to be kept at this lowered level of EE. While the math of the equation is simple, the operationalization has proven to be quite different. In fact, a dominant feature of weight loss is that it produces increases in hunger that appear within the first days, persist into weight loss and for at least a year after the intervention. As such, identifying strategies that abate changes in hunger and facilitate post-weight loss appetite control should be viewed as a central tenant of obesity interventions. However, data points to the possibility that it may well be the reduction in EI needed to produce weight loss that actually increases hunger. If this were to be the case, then forcing lower EI after weight loss likely exacerbates the state of increased hunger, paving the way for weight rebound. If there is somewhat a set value of EI for each individual, then current dietary strategies aimed at tailoring a food landscape conducive of reduced hunger with reduced EI needed to sustain weight loss, are destined to fail.
Primary hypotheses- The increase of EI to pre-weight loss values will significantly attenuate weight loss induced increases in hunger.
Secondary hypothesis- The increase of EI to pre-weight loss values will significantly attenuate weight loss induced metabolic adaptations (Greater than Predicted decreased in EE).
The increase of EI to pre-weight loss will significantly improve post weight loss ghrelin, PYY and GLP-1 responses.
Research plan- Fifty individuals living with obesity (25 men and 25 women BMI ≥ 30 kg/m2) will undergo a 20-week weight-loss intervention. After weight loss they will be randomly assigned to a 1-month experimental condition comprising of either : 1) a weight maintenance diet; or to 2) an increase of EI to pre-weight loss levels combined with increased exercise to maintain energy balance. A detailed investigation of energy balance variables will be conducted at all three time points.
Relevance- Discovery drives paradigm changes, which hold the promise of catalyzing innovation in treatment. The clinical impact of a setpoint EI is that it would inform more tailored personalized dietary intervention based on one's individual pre-weight loss EI rather than post-weight loss outcomes, which is the current standard of care for maintenance of weight loss. In other words, it could inform the precise corrections in EE (from physical activity) needed to not exacerbate appetite control, and to likely favour healthier weights.
- Conditions
- Obesity & Overweight
- Being tested
- Exercise, Dietary Intervention
- Keywords
- Appetite, weight loss, exercise, dietary intervention
- Medical subject headings
- Obesity, Overweight, Weight Loss, Motor Activity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ExerciseBehavioural
Daily kilometer target at normal walking pace (~5km/h). The American College of Sports Medicine (ACSM) metabolic equation for the caloric cost of walking will be used to assess the distance needed to be covered daily.
Dietary InterventionBehavioural
Participants will be prescribed a 20-week energy-restricted diet (-25% of energy requirements). A registered dietitian will be responsible for nutrition counselling and will use the Canadian Diabetes Association's Exchange System to prescribe the diet plan. During the weight loss phase, participants will receive a revised diet plan, based on the adjusted energy requirements that will account for the achieved weight loss.
After weight loss, the diet plan will be revised based on the group (high-energy flux vs low-energy flux) to be in a state of energy balance.
| Study group | Role | What they receive |
|---|---|---|
| High Energy Flux | Experimental | After weight loss through a dietary intervention, the high flux group will remain in a state of energy balance through an increase in exercise and an increase in energy intake to pre-weight loss values. Receives: Behavioral: Exercise; Behavioral: Dietary Intervention |
| Low Energy Flux | Placebo comparator | After weight loss through a dietary intervention, the low-energy flux group will remain in energy balance but at a lower energy flux, with no changes in exercise levels and energy intake remaining lower than pre-weight-loss values. Receives: Behavioral: Dietary Intervention |
What is being measured
The primary outcome is the main question the study is designed to answer.
Appetite measurements
Desire to eat, hunger, fullness, and prospective food consumption (PFC) will be rated immediately before (after a 12 h overnight fast) and every 30 min*3 h after the standardized breakfast on a 100-mm visual analog scale (VAS) adapted from Hill and Blundell. Scores range from 0 to 100 millimeters. For hunger, desire to eat, and prospective food consumption, higher scores indicate greater appetite. For fullness, higher scores indicate greater fullness (lower appetite).
The satiety quotient will be calculated for each subject.
Measured: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Secondary outcomes (16)
Plasma concentrations of appetite-regulating hormones
Blood samples will be collected during experimental sessions while fasting and every 30 minutes for 3 hours following the standardized breakfast. EDTA and Aprotinin (anti-protease) and DPP-IV inhibitors will be added to whole-blood before it is centrifuged at 3000 rpm for 5 minutes at 4˚C. Plasma will be treated within an hour of sampling and then stored at -80˚C until assayed. Total Ghrelin (EZGRT-89K), Leptin (EZHL-80SK), GLP-1 (EZGLP1T-36K) and PYY (EZHPYYT66K) will be assayed with commercially available ELISA (Millipore). All samples from one subject will be assayed in duplicates in the same plate to avoid inter-assay variability.
Measured: Blood samples will be collected at each experimental session: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), and onset of week 25 (after the 1-month weight-maintenance period).
Resting Energy Expenditure
The ventilated hood technique and the Vmax Encore 29 N metabolic cart (SensorMedics Corporation) will be used to perform indirect calorimetry. Carts are calibrated with reference gases each day. Measures will occur between 7:00 and 9:30 am after a 12-h fasting period, while also abstaining from exercise for at least 24 h, always performed in the same room, kept dark and at an ambient temperature of 21° C. Indirect calorimetry will be performed for 30 minutes.
Measured: Resting Energy Expenditure will be measured during the screening session (2 weeks before baseline), at baseline, end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Exercise Energy Expenditure
Free-living exercise energy expenditure will be measured using accelerometry. An accelerometer (Actical-Mini Mitter Co. Inc.) will be worn on the lower back for 7 days at each sampling period.
Exercise energy expenditure will also be measured with a COSMED K4b2 portable indirect calorimeter during in-laboratory exercise sessions completed on the treadmill to confirm the accuracy of exercise energy expenditure.
Measured: Accelerometer: worn for 7 days at each sampling period (screening, week 20 (end of weight loss intervention), weeks 22 and 24 (middle and end of weight maintenance). Exercise energy expenditure will be measured once per week during weight maintenance.
Total Energy Expenditure
Total EE will be determined from doubly-labelled water (DLW) over a 7-day period to estimate carbon dioxide production over time in free-living subjects. After deuterated water is administered, 2H is lost from the body water at an exponential rate. When 18O-water is administered, the 18O is also lost with body water turnover (as per the 2H isotope) and with each molecule of carbon dioxide produced because carbonic anhydrase in the body rapidly facilitates the equilibrium exchange of water and carbon dioxide/carbonic acid oxygen. The difference between the rates of disappearance of 2H and 18O corresponds to the total carbon dioxide production over that period. These rates are determined from urine samples taken at the start and at the end of the measurement period. DLW is the gold standard for assessing free-living EE.
Measured: The DLW dose will be consumed during the screening session, and participants will provide their first urine sample. A second sample will be collected on the following day, and a 3rd 7 days later.
Energy Intake
EI will be measured in the laboratory and in the free-living state for 3 days with a food menu that we have developed and validated. In the laboratory, foods are served upon request, while outside the laboratory, foods are selected and packed away into coolers, somewhat like grocery shopping, and leftovers are brought back with wrappings to assess the weight of foods consumed. Food Processor SQL (ESHA Research Inc.) will be used.
Measured: In-lab energy intake: Baseline, end of week 20 (after the weight-loss intervention), and at the onset of week 25 (after one month of weight maintenance). Free-living energy intake will be measured for 3 days after the screening session.
Food Reward
The Leeds Food Preference Questionnaire, a forced-choice computer task, will be used to evaluate the implicit hedonic wanting (speed and frequency of choice) and the explicit hedonic liking (subjective visual analog scale rating) for different visual food cues, which vary in both fat and sugar content. The task assesses explicit liking and explicit wanting for food stimuli. Scores range from 0 to 100, with higher scores indicating greater liking or wanting for the presented foods. The Leeds Food Preference Questionnaire will be administered both before and after lunch.
Measured: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period). The test lasts approximately 10 minutes.
Olfactory and Taste Performance
Nasal chemosensory and taste performance will be measured with Sniffin' Sticks and taste strips (Burghart Instruments, Wedel, Germany).
Measured: Olfactory and taste performance will be assessed during the in-laboratory at baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Body weight
Body weight (kg) will be measured with a digital scale (BWB-800AS Digital Scale from Tanita Corporation of America).
Measured: Baseline, weeks: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 21, 22, 23, 24, 25.
Height
Height (centimeter) will be measured using a stadiometer (HR-100 Height Rod).
Measured: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Fat-mass
Total body fat mass and percentage of total body fat will be assessed using dual-energy X-ray absorptiometry (DXA) (Lunar Prodigy, GE Medical Systems). Total body fat mass is reported in kilograms (kg), and percentage of total body fat is reported as a percentage (%) of total body weight. Higher values for both measures indicate greater total body fat.
Measured: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Fat-free mass
Total body fat-free mass will be assessed using dual-energy X-ray absorptiometry (DXA) (Lunar Prodigy, GE Medical Systems). Fat-free mass is reported in kilograms (kg) and represents the mass of all non-fat tissues, including muscle, organs, and bone. Higher values indicate greater fat-free mass.
Measured: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Bone mineral content
Total body bone mineral content will be assessed using dual-energy X-ray absorptiometry (DXA) (Lunar Prodigy, GE Medical Systems). Bone mineral content is reported in grams (g). Higher values indicate greater total body bone mineral content.
Measured: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Thermic effect of Food
A standardized breakfast consisting of 2 slices of whole wheat bread (80 g), peanut butter (20 g), strawberry jam (20 g), cheddar cheese 27% milk fat (20 g), and orange juice (250 mL). The total energy content is 575 kcal, and its food quotient will be 0.89 (57% carbohydrates, 13% protein, 30% lipids) for the 3 experimental sessions. Comparable alternatives will be offered in cases of food aversions, intolerances, or allergies. After breakfast, resting energy expenditure will be measured for 30 minutes every hour for a total of 3h. The same protocol described in the "resting energy expenditure section" will be used to assess the thermic effect of food (increase in energy expenditure above fasting values for the digestion, absorption, biosynthesis, and storage of nutrients).
Measured: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Eating behaviour assessed using the Three-Factor Eating Questionnaire-51
Eating behaviour will be assessed using the Three-Factor Eating Questionnaire-51 (TFEQ-51). The questionnaire assesses three domains of eating behaviour: dietary restraint, disinhibition, and perceived hunger. Scores are calculated according to published scoring procedures. Dietary restraint scores range from 0 to 21, disinhibition scores range from 0 to 16, and hunger scores range from 0 to 14. Higher scores indicate greater cognitive restraint, greater disinhibition, and greater susceptibility to hunger, respectively.
Measured: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Health-related quality of life assessed using the 36-Item Short Form Health Survey
Health-related quality of life will be assessed using the 36-Item Short Form Health Survey (SF-36). The SF-36 evaluates eight health domains: physical functioning, role limitations due to physical health, role limitations due to emotional problems, energy/fatigue, emotional well-being, social functioning, pain, general health, and health change. Each domain is scored from 0 to 100, with higher scores indicating better health-related quality of life.
Measured: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Mood assessed using the Positive and Negative Affect Schedule
Mood will be assessed using the Positive and Negative Affect Schedule (PANAS). The questionnaire includes two subscales assessing positive affect and negative affect. Each subscale consists of 10 items scored from 1 to 5, resulting in total scores ranging from 10 to 50 for each subscale. Higher positive affect scores indicate greater positive affect, whereas higher negative affect scores indicate greater negative affect.
Measured: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted31 Jul 2026
- Study start1 Sep 2026 (estimated)
- Primary completion1 Sep 2028 (estimated)
- Study completion1 Sep 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (9)Papers the sponsor has linked to this study.
- Other trials for Obesity & OverweightStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 40 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Ottawa
- Sponsor type
- University, hospital or other
- Collaborators
- Canadian Institutes of Health Research (CIHR)
- Responsible party
- Principal investigator, Eric Doucet, University of Ottawa
- Investigators
- Eric Doucet, PhD, Principal investigator, University of Ottawa
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07739095
- Sponsor's protocol ID
- H-10-25-12071
- Other IDs
- 541343
- Status last verified
- Jul 2026
- First submitted
- 14 Jul 2026
- Last updated
- 31 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Machado AM, Guimaraes NS, Bocardi VB, da Silva TPR, Carmo ASD, Menezes MC, Duarte CK. Understanding weight regain after a nutritional weight loss intervention: Systematic review and meta-analysis. Clin Nutr ESPEN. 2022 Jun;49:138-153. doi: 10.1016/j.clnesp.2022.03.020. Epub 2022 Mar 31.
PubMed 35623805Doucet E, McInis K, Mahmoodianfard S. Compensation in response to energy deficits induced by exercise or diet. Obes Rev. 2018 Dec;19 Suppl 1:36-46. doi: 10.1111/obr.12783.
PubMed 30511511Cameron JD, Goldfield GS, Riou ME, Finlayson GS, Blundell JE, Doucet E. Energy depletion by diet or aerobic exercise alone: impact of energy deficit modality on appetite parameters. Am J Clin Nutr. 2016 Apr;103(4):1008-16. doi: 10.3945/ajcn.115.115584. Epub 2016 Feb 17.
PubMed 26888712Leibel RL, Rosenbaum M, Hirsch J. Changes in energy expenditure resulting from altered body weight. N Engl J Med. 1995 Mar 9;332(10):621-8. doi: 10.1056/NEJM199503093321001.
PubMed 7632212Schwartz A, Doucet E. Relative changes in resting energy expenditure during weight loss: a systematic review. Obes Rev. 2010 Jul;11(7):531-47. doi: 10.1111/j.1467-789X.2009.00654.x. Epub 2009 Sep 17.
PubMed 19761507Dulloo AG, Jacquet J, Girardier L. Poststarvation hyperphagia and body fat overshooting in humans: a role for feedback signals from lean and fat tissues. Am J Clin Nutr. 1997 Mar;65(3):717-23. doi: 10.1093/ajcn/65.3.717.
PubMed 9062520Anderson JW, Konz EC, Frederich RC, Wood CL. Long-term weight-loss maintenance: a meta-analysis of US studies. Am J Clin Nutr. 2001 Nov;74(5):579-84. doi: 10.1093/ajcn/74.5.579.
PubMed 11684524Ryan DH. Risks and benefits of weight loss: challenges to obesity research. European Heart Journal 2005; (7): L27-L31.
Anderson JW, Luan J, Hoie LH. Structured weight-loss programs: meta-analysis of weight loss at 24 weeks and assessment of effects of intervention intensity. Adv Ther. 2004 Mar-Apr;21(2):61-75. doi: 10.1007/BF02850334.
PubMed 15310080
Study at a glance
From the registry record, last updated by the sponsor on 31 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Weight Loss and Hunger: Did we Get it Wrong All This Time?
- ClinicalTrials.gov ID
- NCT07739095
- Acronym / sponsor ID
- H-10-25-12071
- Conditions
- Obesity & Overweight
- Keywords
- Appetite, weight loss, exercise, dietary intervention
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 40 participants (estimated)
- Lead sponsor
- University of OttawaUniversity, hospital or other
- Collaborators
- Canadian Institutes of Health Research (CIHR)
- Study start
- 1 Sep 2026 (estimated)
- Primary completion
- 1 Sep 2028 (estimated)
- Study completion
- 1 Sep 2028 (estimated)
- First posted
- 31 Jul 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Weight loss is difficult and weight maintenance even worse. The principles of dieting dictate that to maintain weight loss, one has to eat less calories than they did before the diet. However, there is evidence to show that it may be the diet per se and not the weight loss that makes people more hungry and vulnerable to weight regain. This study will explore whether appetite control can be restored to normal levels through an individually tailored increase in calories after weight loss. If supported, the findings from this study could alter the way we view dieting.
Detailed description
Weight loss reduces all components of the energy budget, i.e. resting energy expenditure (EE), the thermic effect of feeding and the energy cost of physical activities. The corollary of this observation is that to achieve energy balance at a lowered body weight (if EE is not increased through purposeful physical activity), energy intake (EI) needs to be kept at this lowered level of EE. While the math of the equation is simple, the operationalization has proven to be quite different. In fact, a dominant feature of weight loss is that it produces increases in hunger that appear within the first days, persist into weight loss and for at least a year after the intervention. As such, identifying strategies that abate changes in hunger and facilitate post-weight loss appetite control should be viewed as a central tenant of obesity interventions. However, data points to the possibility that it may well be the reduction in EI needed to produce weight loss that actually increases hunger. If this were to be the case, then forcing lower EI after weight loss likely exacerbates the state of increased hunger, paving the way for weight rebound. If there is somewhat a set value of EI for each individual, then current dietary strategies aimed at tailoring a food landscape conducive of reduced hunger with reduced EI needed to sustain weight loss, are destined to fail.
Primary hypotheses- The increase of EI to pre-weight loss values will significantly attenuate weight loss induced increases in hunger.
Secondary hypothesis- The increase of EI to pre-weight loss values will significantly attenuate weight loss induced metabolic adaptations (Greater than Predicted decreased in EE).
The increase of EI to pre-weight loss will significantly improve post weight loss ghrelin, PYY and GLP-1 responses.
Research plan- Fifty individuals living with obesity (25 men and 25 women BMI ≥ 30 kg/m2) will undergo a 20-week weight-loss intervention. After weight loss they will be randomly assigned to a 1-month experimental condition comprising of either : 1) a weight maintenance diet; or to 2) an increase of EI to pre-weight loss levels combined with increased exercise to maintain energy balance. A detailed investigation of energy balance variables will be conducted at all three time points.
Relevance- Discovery drives paradigm changes, which hold the promise of catalyzing innovation in treatment. The clinical impact of a setpoint EI is that it would inform more tailored personalized dietary intervention based on one's individual pre-weight loss EI rather than post-weight loss outcomes, which is the current standard of care for maintenance of weight loss. In other words, it could inform the precise corrections in EE (from physical activity) needed to not exacerbate appetite control, and to likely favour healthier weights.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| High Energy Flux | Experimental | Behavioral: Exercise, Behavioral: Dietary InterventionAfter weight loss through a dietary intervention, the high flux group will remain in a state of energy balance through an increase in exercise and an increase in energy intake to pre-weight loss values. |
| Low Energy Flux | Placebo comparator | Behavioral: Dietary InterventionAfter weight loss through a dietary intervention, the low-energy flux group will remain in energy balance but at a lower energy flux, with no changes in exercise levels and energy intake remaining lower than pre-weight-loss values. |
Who may qualify
- Ages
- 18 to 55 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (7 listed)
- 18-55 years of age;
- non-smoking;
- obese class I-II (30 kg/m2 ≤ BMI < 40 kg/m2);
- weight stable (± 2 kg during the 6 months prior to enrollment);
- Sedentary (<2 times/week of 30 min of continuous exercise)
Key exclusion criteria (11 listed)
- have a current diagnosis of an axis 1 psychiatric disorder (i.e. mood, anxiety and eating disorders);
- currently use antidepressants, thyroid medication, or any medication that could affect appetite;
- have a history of cardiac problems or symptoms suggestive of any cardiac condition;
- have a current diagnosis or history of diabetes, confirmed by a measure of HbA1c during the screening visit;
- have alcohol intake that exceeds recommendations or alcoholism, or current addictions to opiates, cocaine or stimulants;
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ExerciseDaily kilometer target at normal walking pace (~5km/h). The American College of Sports Medicine (ACSM) metabolic equation for the caloric cost of walking will be used to assess the distance needed to be covered daily. | Behavioural | High Energy Flux |
| Dietary InterventionParticipants will be prescribed a 20-week energy-restricted diet (-25% of energy requirements). A registered dietitian will be responsible for nutrition counselling and will use the Canadian Diabetes Association's Exchange System to prescribe the diet plan. During the weight loss phase, participants will receive a revised diet plan, based on the adjusted energy requirements that will account for the achieved weight loss. After weight loss, the diet plan will be revised based on the group (high-energy flux vs low-energy flux) to be in a state of energy balance. | Behavioural | High Energy Flux, Low Energy Flux |
Primary outcome
Appetite measurements
Time frame: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Desire to eat, hunger, fullness, and prospective food consumption (PFC) will be rated immediately before (after a 12 h overnight fast) and every 30 min*3 h after the standardized breakfast on a 100-mm visual analog scale (VAS) adapted from Hill and Blundell. Scores range from 0 to 100 millimeters. For hunger, desire to eat, and prospective food consumption, higher scores indicate greater appetite. For fullness, higher scores indicate greater fullness (lower appetite). The satiety quotient will be calculated for each subject.
16 secondary outcomes
Plasma concentrations of appetite-regulating hormones
Time frame: Blood samples will be collected at each experimental session: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), and onset of week 25 (after the 1-month weight-maintenance period).
Resting Energy Expenditure
Time frame: Resting Energy Expenditure will be measured during the screening session (2 weeks before baseline), at baseline, end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Exercise Energy Expenditure
Time frame: Accelerometer: worn for 7 days at each sampling period (screening, week 20 (end of weight loss intervention), weeks 22 and 24 (middle and end of weight maintenance). Exercise energy expenditure will be measured once per week during weight maintenance.
Total Energy Expenditure
Time frame: The DLW dose will be consumed during the screening session, and participants will provide their first urine sample. A second sample will be collected on the following day, and a 3rd 7 days later.
Energy Intake
Time frame: In-lab energy intake: Baseline, end of week 20 (after the weight-loss intervention), and at the onset of week 25 (after one month of weight maintenance). Free-living energy intake will be measured for 3 days after the screening session.
Food Reward
Time frame: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period). The test lasts approximately 10 minutes.
Olfactory and Taste Performance
Time frame: Olfactory and taste performance will be assessed during the in-laboratory at baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Body weight
Time frame: Baseline, weeks: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 21, 22, 23, 24, 25.
Height
Time frame: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Fat-mass
Time frame: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Fat-free mass
Time frame: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Bone mineral content
Time frame: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Thermic effect of Food
Time frame: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Eating behaviour assessed using the Three-Factor Eating Questionnaire-51
Time frame: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Health-related quality of life assessed using the 36-Item Short Form Health Survey
Time frame: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Mood assessed using the Positive and Negative Affect Schedule
Time frame: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 31 Jul 2026.
- Background: PubMed 35623805Machado AM, Guimaraes NS, Bocardi VB, da Silva TPR, Carmo ASD, Menezes MC, Duarte CK. Understanding weight regain after a nutritional weight loss intervention: Systematic review and meta-analysis. Clin Nutr ESPEN. 2022 Jun;49:138-153. doi: 10.1016/j.clnesp.2022.03.020. Epub 2022 Mar 31.
- Background: PubMed 30511511Doucet E, McInis K, Mahmoodianfard S. Compensation in response to energy deficits induced by exercise or diet. Obes Rev. 2018 Dec;19 Suppl 1:36-46. doi: 10.1111/obr.12783.
- Background: PubMed 26888712Cameron JD, Goldfield GS, Riou ME, Finlayson GS, Blundell JE, Doucet E. Energy depletion by diet or aerobic exercise alone: impact of energy deficit modality on appetite parameters. Am J Clin Nutr. 2016 Apr;103(4):1008-16. doi: 10.3945/ajcn.115.115584. Epub 2016 Feb 17.
- Background: PubMed 7632212Leibel RL, Rosenbaum M, Hirsch J. Changes in energy expenditure resulting from altered body weight. N Engl J Med. 1995 Mar 9;332(10):621-8. doi: 10.1056/NEJM199503093321001.
- Background: PubMed 19761507Schwartz A, Doucet E. Relative changes in resting energy expenditure during weight loss: a systematic review. Obes Rev. 2010 Jul;11(7):531-47. doi: 10.1111/j.1467-789X.2009.00654.x. Epub 2009 Sep 17.
- Background: PubMed 9062520Dulloo AG, Jacquet J, Girardier L. Poststarvation hyperphagia and body fat overshooting in humans: a role for feedback signals from lean and fat tissues. Am J Clin Nutr. 1997 Mar;65(3):717-23. doi: 10.1093/ajcn/65.3.717.
- Background: PubMed 11684524Anderson JW, Konz EC, Frederich RC, Wood CL. Long-term weight-loss maintenance: a meta-analysis of US studies. Am J Clin Nutr. 2001 Nov;74(5):579-84. doi: 10.1093/ajcn/74.5.579.
- BackgroundRyan DH. Risks and benefits of weight loss: challenges to obesity research. European Heart Journal 2005; (7): L27-L31.
- Background: PubMed 15310080Anderson JW, Luan J, Hoie LH. Structured weight-loss programs: meta-analysis of weight loss at 24 weeks and assessment of effects of intervention intensity. Adv Ther. 2004 Mar-Apr;21(2):61-75. doi: 10.1007/BF02850334.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Eric Doucet, PhD principal investigator
University of Ottawa
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Exercise and Dietary Intervention in people with Obesity & Overweight, run by University of Ottawa at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 11 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 31 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Eric Doucet, PhD (613-562-5800 ext. 4271, edoucet@uOttawa.ca), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Appetite measurements (time frame: Baseline (1 week before the dietary intervention), end of week 20 (after the weight-loss intervention), onset of week 25 (after the 1-month weight-maintenance period).). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07739095, which also lists 9 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 31 Jul 2026.