CClinicalTrials.gg
CompletedNCT02736669CAREUpdated Dec 17, 2025

CARE Trial: Comparing Different Levels of Calorie Reduction for Weight Loss

An interventional study of Energy Reduction in Overweight and Obesity, sponsored by University of Alabama at Birmingham. Completed at 1 site in United States. Open to participants aged 21 Years to 75 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-12-17.

Sponsored by University of Alabama at Birmingham · Not applicable, Interventional, and Treatment

From the registry’s dates

  • Registered 6 months after the study started (first participant enrolled Oct 2015, registered Apr 2016).
Phase
Not applicable
Study type
Interventional
Enrollment
223
Allocation
Randomized
Ages
21 Years to 75 Years
Sex
All
01

Study summary

This research study will compare two weight loss programs that provide different recommendations for how to reduce your energy (or calorie) intake to achieve weight loss in an effort to determine if fixed calorie reduction or varied calorie reduction is more effective for weight loss.

02

Conditions studied

  • Overweight
  • Obesity

Keywords

  • weight loss
  • body weight
  • behavioral
03

In context

Overweight

3,670 studies on the registry are indexed under Overweight; 850 are open to participants now.

This study's enrollment of 223 is above the median of 73 across 3,175 interventional studies indexed under Overweight.

Browse Overweight studies →

Lead sponsor

University of Alabama at Birmingham is the lead sponsor of 1,396 studies on the registry; 284 are open to participants now.

Of its 156 completed or terminated interventional studies of FDA-regulated products, 124 (79%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
21 Years to 75 Years
Sexes eligible
All
Accepts healthy volunteers
Yes

Inclusion criteria

  • Age 21-75
  • Body mass index (BMI) 30-50 kg/m2

Exclusion criteria

Exclusion Criteria:

  • Uncontrolled hypertension (blood pressure >160/100 mm Hg)
  • Any of the following other medical conditions: myocardial infarction or cerebrovascular accident within the last six months; unstable angina within the past six months; congestive heart failure; cancer requiring treatment in past five years (exception: non-melanoma skin cancer); serious infectious diseases (e.g., self-reported HIV); chronic hepatitis; cirrhosis; chronic malabsorption syndrome; chronic pancreatitis; chronic lung diseases or orthopedic problems that limit physical activity
  • Current use of any of the following medications: antipsychotic agents, monoamine oxidase inhibitors, systemic corticosteroids, antibiotics for HIV or TB, or chemotherapeutic drugs; prescription weight loss medications (past six months)
  • Unwilling or unable to do any of the following: give informed consent; read English at the 5th grade level; accept random assignment; travel to the intervention site
  • Likely to relocate out of the area in the next 2 years
  • Participation in another randomized research project
  • Weight loss > 10 pounds in past six months
  • History of bariatric surgery
  • Major depressive or psychiatric disorder, or excessive alcohol intake
  • Potential participants living farther than 30 miles driving distance from UAB will be excluded from the study.
  • Potential participants (female) that are pregnant or plan to become pregnant in the next 18 months will be excluded from participation in the study. This is a weight loss study and weight gain/loss due to pregnancy and/or delivery would confound study results. Additionally, weight loss is not recommended for pregnant women.
05

Study design

Phase
Not applicable
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Single (Outcomes assessor)
Enrollment
223 participants (actual)

Study arms

  • Active comparator
    Fixed Energy (or Calorie) Reduction

    Participants randomly assigned to this arm will be instructed to reduce their food intake by a moderate amount and stay at this level of moderate reduction until their weight loss goal is achieved.

    Behavioral: Energy Reduction

  • Experimental
    Variable Energy (or Calorie) Reduction

    Participants randomly assigned to this arm will be instructed to alternate between two levels of calorie reduction. One level will be a small amount of calorie reduction, while the other will be a more significant amount of calorie reduction. At the instruction of the research team, participants will periodically alternate back and forth between these two goals until their weight loss goal is achieved.

    Behavioral: Energy Reduction

Interventions

  • BehavioralEnergy Reduction
06

What researchers measure

Primary outcomes

  1. Measure change in body weight (kg) from baseline to follow-up assessments

    Participants will be weighed by body scale in kilograms

    Time frame: Baseline, 6 months, 18 months

Secondary outcomes

  1. Resting energy expenditure

    An indirect calorimeter with the ventilated hood technique will be used for the 30-minute measurement (the first 10 minutes will be excluded from analysis). The respiratory quotient will be calculated as the ratio of carbon dioxide production to oxygen consumption. Resting metabolic rate will be calculated from VO2 and VCO2 measurements using the Weir equation.

    Time frame: 6, 12, and 18 months

  2. Body composition

    Assessed by full body DXA scan to evaluate percentage of body fat.

    Time frame: 6, 12, and 18 months

  3. Laboratory analyses

    Glucose, lipids, and insulin will be analyzed using blood samples.

    Time frame: 6, 12, and 18 months

  4. Blood pressure

    After a 5 minute seated rest, three measurements using an automated blood pressure device will be taken to obtain the average systolic and diastolic blood pressures.

    Time frame: 6, 12, and 18 months

  5. Hormones - ghrelin

    Total ghrelin will be assessed using blood samples.

    Time frame: 6, 12, and 18 months

  6. Hormones - leptin

    Total leptin will be assessed using blood samples.

    Time frame: 6, 12, and 18 months

  7. Satiety/hunger

    Visual analogue scales (VAS) will be used to measure subjective ratings of appetite. Participants will be asked to provide a rating in response to several questions (e.g., "How hungry did you feel this week? How much did you think about food this week?") using a 100-mm line ranging from "not at all" to "extremely".

    Time frame: 6, 12, and 18 months

  8. Physical activity - objective

    Will be assessed via accelerometers worn by participants for seven days. Participants will be instructed to position the accelerometer at the right hip and to wear the device throughout the day except when sleeping, bathing, or participating in swimming or other water activities. These data will be used to estimate total minutes of moderate- to vigorous-intensity PA.

    Time frame: 6, 12, and 18 months

  9. Physical activity - self-report

    Self-reported PA will also be assessed with the Paffenbarger Physical Activity Questionnaire (PPAQ). Both methods of PA measurement are included, as accelerometers provide objective information about total levels of activity, while the PPAQ provides additional details about the type and schedule of activities.

    Time frame: 6, 12, and 18 months

  10. Treatment adherence

    Treatment adherence will be assessed by the number of treatment sessions attended as well as the number of self-monitoring forms completed, which have both been used as indicators of adherence in our previous work

    Time frame: 6, 12, and 18 months

  11. Treatment novelty

    This construct will be evaluated with a 6-item measure of treatment reinforcement that assesses the extent to which participants enjoy and become less habituated to the behavioral strategies required for weight loss.

    Time frame: 6, 12, and 18 months

  12. Treatment burden

    Behavioral burden of treatment will be assessed with a modified version of the Treatment Burden Questionnaire (TBQ), which includes 15 items measuring the burden of treatment, including behaviors of self-monitoring, dietary changes, maintaining physical activity, and the impact of treatment on social relationships.

    Time frame: 6, 12, and 18 months

  13. Treatment satisfaction

    Participants will complete a modified version of the Treatment Satisfaction Questionnaire for Medication (TSQM) to assess attitudes and satisfaction regarding the weight loss intervention, energy prescriptions provided, and weight loss achieved. A composite score of treatment satisfaction will be calculated based on participants' responses.

    Time frame: 6, 12, and 18 months

07

Study locations

1 site
  • University of Alabama at Birmingham, Medical Towers Building
    Birmingham, Alabama 35205, United States
08

References and documents

Individual participant data

Plan to share: Yes — The PI will ensure all publications that result from project-related data will comply with the NIH public access policy and develop a system by which study data may be shared with other investigators within the scientific community. With UAB IRB permission, PI may develop a de-identified database, codebook, and mechanism by which data can be shared with qualified individuals/organizations. PI will keep a record of all individuals/res. teams who request/receive a copy of the data. Interested investigators will be asked to complete a request form stating specific aims of the analyses, analytic plan, available resources, proposed timeline, and goals. PI and team will review these requests to determine whether proposed analyses constitute significant exploration of the data, team has resources to complete request, and data will be adequately protected and managed. If any issues are problematic, PI and team will attempt to negotiate a fair resolution with investigators and NIH staff.

No publications or documents are linked to this record.

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Dec 17, 2025, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT02736669
Lead sponsor
University of Alabama at Birmingham
Collaborators
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Responsible party
Gareth R. Dutton PhD (Associate Professor, University of Alabama at Birmingham) — Principal investigator
First posted
Apr 13, 2016
Start date
Oct 2015
Primary completion
Apr 30, 2021
Completion
Dec 1, 2025
Last update
Dec 17, 2025

Study contacts

Gareth R Dutton, PhD
principal investigator · University of Alabama at Birmingham, Department of Medicine, Division of Preventive Medicine

Oversight

Data monitoring committee
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is completed, as verified in Dec 2025. You cannot join it, but the record below documents what was studied.

Follow this study

Get an email when the registry record changes — status, dates, results — or when someone posts here.

Sign in to follow

Discussion

Questions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.

Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.

Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.

Start the discussion