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Energy Expenditure and Weight Loss Maintenance

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT03422380
Recruitment Status : Completed
First Posted : February 5, 2018
Last Update Posted : February 5, 2018
National Institutes of Health (NIH)
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Information provided by (Responsible Party):
University of Colorado, Denver

Brief Summary:
Obesity is reaching epidemic proportions and threatens both health and quality of life of people around the world. While many individuals succeed at short term weight loss, weight loss maintenance is the greatest barrier to successful treatment of obesity. High levels of physical activity are consistently associated with success in weight loss maintenance. The major goal of this proposal is to understand how and why high levels of physical activity are critical for long term maintenance of weight loss. This project takes advantage of the National Weight Control Registry (NWCR), which follows over 6000 individuals who have maintained a weight loss of ≥30 pounds for ≥1 year. Understanding how individuals successful at weight loss maintenance achieve energy balance will provide important insight into strategies to help more people sustain a weight loss.

Condition or disease
Obesity Weight Change, Body Weight Loss Physical Activity

Detailed Description:
Participants were recruited in three groups: weight loss maintainers (WLM: maintaining ≥13.6 kg weight loss for ≥1 year), normal weight controls (NC: Body Mass Index (BMI) matched to current BMI of WLM), and controls with overweight/obesity (Overweight Controls (OC): BMI matched to pre-weight loss maximum BMI of WLM). The investigators hypothesize that total daily energy expenditure (TDEE) in WLM is similar to OC but is significantly higher then NC. High levels of volitional physical activity may compensate for the reduction in energy expenditure ("energy gap") that is the expected result of weight loss. This allows WLM to maintain a high level of "energy flux", which may facilitate optimal body weight regulation over time. The investigators will use doubly labeled water to compare TDEE in WLM and both NC and OC. The investigators will also compare individual components of TDEE including resting energy expenditure (REE), thermic effect of food (TEF), physical activity energy expenditure (PAEE), and physical activity level (PAL) between groups. The investigators also hypothesize that REE in WLM is similar to controls of both types under free living conditions, but will decrease following a period of physical inactivity and be significantly less than controls. Studies in rodents have consistently shown evidence of an increase in metabolic efficiency in the reduced obese state manifested by a lower than predicted REE. Studies in humans have shown mixed results, however few studies have controlled for habitual level of physical activity. Recent evidence suggests REE is greater in adults who perform regular exercise than their sedentary peers; this difference can be attributed in part to greater tonic sympathetic nervous system stimulation of REE that occurs in habitually exercising adults. The investigators believe there is an increase in metabolic efficiency in the reduced obese state manifested by a lower than predicted REE, and that high levels of physical activity function to "mask" or "correct" this metabolic efficiency. The investigators will compare REE under free living conditions and during an experimentally imposed period of reduced energy flux (restricted physical activity matched by an equivalent reduction in energy intake) in WLM and controls.

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Study Type : Observational
Actual Enrollment : 112 participants
Observational Model: Case-Control
Time Perspective: Cross-Sectional
Official Title: Energy Expenditure in Subjects Successful at Weight Loss Maintenance
Actual Study Start Date : October 2009
Actual Primary Completion Date : September 2012
Actual Study Completion Date : September 2012

Resource links provided by the National Library of Medicine

Weight Loss Maintainers (WLM)
Individuals maintaining ≥13.6 kg (30 lb) weight loss for ≥1 year
Normal Weight Controls (NC)
Individuals with normal weight whose BMI was matched to the current BMI of the WLM. NC had to be weight stable and not maintaining a weight loss of ≥13.6kg
Controls with Overweight/Obesity (OC)
Individuals with overweight/obesity whose BMI was matched to the pre-weight loss maximum BMI of WLM. OC had to be weight stable and not maintaining a weight loss of ≥13.6kg

Primary Outcome Measures :
  1. Total Daily Energy Expenditure (TDEE) [ Time Frame: At 8 days ]
    After a 12-hour overnight fast, participants provided a baseline urine sample on day 1. Participants were then administered an oral dose of doubly labeled water (DLW) containing 1.8g 10% 18O/kg total body water (TBW) and 0.12 g/kg TBW of 99.9% deuterium. TBW was estimated as 73% of FFM from DXA. The dosing cup was rinsed twice with 30 mL of water and the rinsing dose consumed. Exact time of dosing was recorded. Additional urine samples were collected after a 4hr and 5hr post-dose equilibrium period and then again at the same times on day 8. TDEE over days 1-8 was determined using a single DLW dose and the two-point method according to Schoeller and colleagues.

Secondary Outcome Measures :
  1. Physical Activity Energy Expenditure (PAEE) [ Time Frame: At 8 days ]
    PAEE was calculated as TDEE - TEF - REE. In addition, because the energy cost of PA is proportional to body weight for a given intensity and duration, PAEE was also calculated as relative to body weight (kg).

  2. Resting Energy Expenditure (REE) [ Time Frame: Day 1 and Day 8 over a 1 week period ]
    REE was measured using standard indirect calorimetry (Truemax 2400, ParvoMedics, Salt Lake City, UT) with the ventilated hood technique. Study participants arrived at 7am after a 12-hour overnight fast. Participants rested supine, awake, and lightly clothed in a thermoneutral (68-74 ˚F), dimly lit, quite room for 30 minutes. Respiratory gas exchange was measured for 15 minutes, using the last 10 minutes to average REE. Tests were examined for validity to confirm a) average RQ was 0.7-0.9, and b) average Metabolic Equivalents (METs) <1.10. If the averaged data fell outside of these ranges, the test was considered invalid and excluded from the analysis. REE was collected on days 1 and 8 of the free-living monitoring period, and averaged to produce a single value for REE (intraclass correlation coefficient = 0.96).

  3. Thermic Effect of Food (TEF) [ Time Frame: At 8 days ]
    The thermic effect of food (TEF) was calculated as 10% of TDEE.

  4. Physical Activity Level (PAL) [ Time Frame: At 8 days ]
    PAL was calculated as TDEE/REE.

Other Outcome Measures:
  1. Physical Activity Patterns [ Time Frame: At 8 days ]
    PA patterns were assessed using the activPALTM activity monitor (PAL Technologies, Glasgow, Scotland). The activPALTM is a small (23x43x5 mm) and lightweight (10 grams) device that uses accelerometer-derived information about thigh position to estimate time spent sitting/lying, standing, and stepping. The device is attached to the anterior thigh and is waterproofed by wrapping it in a nitrile sleeve, allowing for 24-hour measurement. Participants were asked to wear the device continuously for seven days.

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 65 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Sampling Method:   Non-Probability Sample
Study Population
The proposed study design is aimed at collecting additional data on previously enrolled adult study subjects in the NWCR, which does not include children. The NWCR contains approximately 70% women and 30% men. We anticipate studying equal numbers of men and women in this study. Minorities comprise approximately 7% of total subjects in the NWCR. In the proposed studies, there will be no exclusions for racial or ethnic background.

Inclusion Criteria:

  • Men or women
  • Age 18-65
  • Weight stable (<10 lb fluctuation in body weight over previous 6 months) or
  • NWCR subjects successful at weight loss maintenance (maintaining a loss of ≥ 30 pounds for at least 2 years)
  • Non-Reduced Weight Matched Controls: Individuals matched to NWCR subjects' current body weight. These individuals will be normal weight (BMI 18-25, BMI up to 27 allowed in men with waist circumference < 40 cm), and have no history of overweight or obesity (BMI >25) and will not be maintaining a weight loss ≥ 30 pounds.
  • Non-Reduced Obese Controls: Individuals matched to NWCR subjects' maximum pre-weight loss body weight. These individuals will be overweight or obese (BMI ≥ 26-45).

Exclusion Criteria:

  • Diabetes
  • Uncontrolled HTN (>160/100)
  • History of cardiac disease: CHF or angina, atrial fibrillation or ventricular tachycardia, or significant abnormality on resting EKG
  • Symptoms suggestive of cardiovascular disease: chest pain, shortness of breath at rest or with mild exertion, dizziness, syncope.
  • History of neurological disease: stroke, TIA or seizure disorder
  • Current treatment for cancer (except skin)
  • Severe pulmonary, liver or kidney disease
  • Untreated thyroid disorder
  • Severe arthritis or other musculoskeletal disorder
  • Alcohol or drug abuse
  • Active psychiatric illness
  • Positive response to PAR-Q indicating requirement for monitored physical activity
  • Other serious medical condition as determined by the investigator which would limit physical activity or require monitored activity.
  • Pregnant and lactating women, and women actively trying to become pregnant (post-menopausal women on a stable dose of HRT and pre-menopausal women on a stable OCP regimen will be allowed to participate)
  • Smoking within the past 6 months
  • Subjects using prescription or over the counter medication which may affect RMR including beta blockers, stimulants such as Ritalin and appetite suppressants.
  • Subjects who have undergone bariatric surgery or who are currently maintaining their weight loss with prescription weight loss drugs or supplements.
  • Severe claustrophobia
  • Moderate or high levels of physical activity at the workplace and unable to reduce workplace activity, work from home or take time off from work to participate in Study 2.
  • We will exclude controls if they are weight reduced (maintaining a weight loss of ≥ 30 pounds).

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT03422380

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United States, Colorado
University of Colorado Anschutz Medical Campus
Aurora, Colorado, United States, 80045
Sponsors and Collaborators
University of Colorado, Denver
National Institutes of Health (NIH)
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
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Principal Investigator: Victoria Catenacci, MD University of CO
Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: University of Colorado, Denver Identifier: NCT03422380    
Other Study ID Numbers: 07-0584
1K23DK078913 ( U.S. NIH Grant/Contract )
First Posted: February 5, 2018    Key Record Dates
Last Update Posted: February 5, 2018
Last Verified: January 2018

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by University of Colorado, Denver:
energy expenditure
adaptive thermogenesis
metabolic adaptation
weight loss maintenance
Additional relevant MeSH terms:
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Body Weight
Weight Loss
Body Weight Changes