Health TrialsbyHealthPanel

Weight Loss and Hunger

ConditionObesity & Overweight
Trial statusNot yet recruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-55
SponsorUniversity of Ottawa

About this trial

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.

Eligibility criteria

This trial does not accept healthy volunteers

Qualifiers

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);

Disqualifiers

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;

Trial design

Design model

Parallel

Treatments tested in this trial

  • Exercise

    Behavioral

    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 Intervention

    Behavioral

    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.

Treatment groups

40 Participants
are divided into 2 treatment groups
Group A: High Energy FluxExperimental treatment 2 interventions
Group B: Low Energy FluxPlacebo comparator 1 intervention

Trial outcomes

Primary outcomes

1

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.

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).

Secondary outcomes

1

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.

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).
2

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.

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).
3

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.

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.
4

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.

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.

Other outcomes

Sponsors and contacts

Click on the lead sponsor to view all of their trials.

University of Ottawa

Lead sponsor

Canadian Institutes of Health Research (CIHR)

Collaborator

Source ClinicalTrials.gov

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