Obesity
Conditions
Brief summary
The primary aim of this study is to is to determine if intermittent fasting (IMF) is an effective dietary strategy for treatment of obesity. A 1 year randomized trial will be used to compare weight loss generated by IMF versus Daily Caloric Restriction (DCR). The targeted weekly energy deficit is designed to be similar (\ 30%) and a comprehensive behavioral support program will be provided to both groups. The primary outcome is weight change at the end of the 1 year intervention; follow up measures will also be obtained 6 months after completing the intervention. This study will provide robust data regarding weight loss effectiveness of IMF and will further our understanding of the impact of IMF on energy balance.
Detailed description
Restricting daily calorie intake is the primary dietary strategy currently used to treat obesity. However, this approach is not effective for all individuals. Further, adherence to daily caloric restriction (DCR) typically decreases over time and many individuals who lose weight with this strategy will regain. Thus, novel dietary interventions are needed to provide a broader range of treatment options. The objective of this proposal is to determine if intermittent fasting (IMF) is an effective dietary strategy for treatment of obesity. IMF is an alternative method of reducing energy intake (EI) which has gained lay popularity in recent years as a strategy for weight loss. Short-term studies suggest IMF produces 3-8% weight loss in individuals with overweight and obesity. However, few studies have compared IMF to DCR and no studies have evaluated whether IMF is an effective long-term (≥1 year) weight loss strategy. Data from an 8-week pilot study comparing IMF to DCR suggests IMF is safe, tolerable, and produces similar short-term weight loss. After 6 months of unsupervised follow-up, changes in body composition tended to be more favorable with IMF and almost twice as many IMF participants maintained a ≥5 kg weight loss. Thus, IMF may be a more effective dietary strategy for sustaining weight loss than DCR. However, longer-term data are needed and little is known about adherence to IMF or the impact of IMF on energy expenditure (EE). Short-term studies suggest adherence to IMF may be superior to DCR, however, energy intake (EI) was based on self-report which may have significant limitations. Pilot data suggests resting energy expenditure (REE) was preserved during IMF-induced weight loss, which could decrease risk for weight regain. However, the impact of IMF on other components of EE including physical activity (PA) is largely unexamined. The study design is a pragmatic randomized trial to compare weight loss generated by IMF vs DCR. The targeted weekly energy deficit will be equivalent: DCR will be prescribed a \ 30% daily energy restriction and IMF will be prescribed a modified fast (\ 80% energy restriction) on 3 non-consecutive days per week. The hypothesis is that a weight loss program based on IMF as the primary dietary strategy will result in greater weight loss at 1 year compared to a program based on traditional DCR. The approach is innovative as the targeted energy deficit will be matched between groups and EI will be assessed objectively (using doubly-labeled water) to provide an accurate comparison of adherence. In addition, both intervention groups will receive guidelines-based behavioral support to compare IMF to the current standard of care (DCR) in a more robust fashion. This study is significant as it could identify an effective alternative dietary strategy to help more people achieve and sustain weight loss.
Interventions
BEHAVIORALDaily Caloric Restriction (DCR)
Participants in this group will be given a calorie goal designed to produce a 34.3% energy deficit from estimated baseline weight maintenance energy requirements. Participants in this group will also receive a 12 month comprehensive group-based behavioral weight loss program and will be instructed in specific strategies to support DCR. Randomized groups will meet separately. Participants in this group will also be asked to increase moderate intensity physical activity to a target of 300 minutes per week.
BEHAVIORALIntermittent Fasting (IMF)
Participants in this group will be instructed to limit energy intake to 20% of estimated baseline energy requirements on three non-consecutive days per week, and to eat ad libitum the other 4 days per week. Participants in this group will also receive a 12 month comprehensive group based behavioral weight loss program and will be instructed in specific strategies to support IMF. Randomized groups will meet separately. Participants in this group will also be asked to increase moderate intensity physical activity to a target of 300 minutes per week.
Sponsors
University of Colorado, Denver
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 60 Years
Healthy volunteers
Yes
Inclusion criteria
* Female or Male * Age 18-60 years * Body Mass Index 27-46 kg/m2 * Sedentary: defined as \<150 minutes per week of voluntary exercise at moderate intensity or greater and \< 60 min per day of total habitual physical activity (i.e. work related, transportation related) at moderate intensity or greater, over the past 3 months. * No self-report of acute or chronic disease (cardiovascular disease (CVD), diabetes, gastrointestinal disorders and orthopedic problems in particular) * No plans to relocate within the next 12 months * No plans for extended travel (\> 2 weeks) within the next 12 months * No nicotine use * Live or work within 30 minutes of the Anschutz Health and Wellness Center (AHWC) (exceptions may be made at the discretion of the Study PI on a case by case basis for highly motivated subjects). * Capable and willing to give informed consent, understand
Exclusion criteria
, and accept the randomized group assignment. * Have a primary care physician (or are willing to establish care with a primary care physician prior to study enrollment) to address medical issues which may arise during screening or study procedures/interventions. * For Females * Not currently pregnant or lactating * Not pregnant within the past 6 months * Not planning to become pregnant in the next 12 months; * Sexually active women of childbearing potential may be enrolled if they have had a tubal ligation or use a reliable means of contraception
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Body Weight | Baseline and weeks 4, 13, 26, 39, 52. | Body weight will be measured via clinic scale. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in Body Weight | Week 78. | Body weight will be measured via clinic scale. The 78 month time point was added via a protocol amendment after study start. This is not a primary outcome, but rather a 6-month post-primary outcome follow-up weight. |
| Changes in Body Composition | Baseline and weeks 26, 52, and 78. | Body composition will be assessed with dual-energy x-ray absorptiometry (DXA).The 78 week time point was added via a protocol amendment after study start. This is not a primary outcome, but rather a 6-month post-primary outcome follow-up measure. |
| Changes in Blood Pressure | Baseline and weeks 13, 26, 52, and 78. | Blood pressure will be measured with a sphygomanometer. The 78 week time point was added via a protocol amendment after study start. This is not a primary outcome, but rather a 6-month post-primary outcome follow-up measure. |
| Changes in Fasting Lipids | Baseline and weeks 26, 52, and 78. | 12 hour fasting blood sample for measurement of lipid profile.The 78 week time point was added via a protocol amendment after study start. This is not a primary outcome, but rather a 6-month post-primary outcome follow-up measure. |
| Changes in Insulin Sensitivity | Baseline and weeks 26, 52, and 78. | 12 hour fasting blood sample for measurement of insulin and glucose. Insulin sensitivity (homeostasis model assessment of insulin resistance \[HOMA-IR\]) will be calculated as (\[insulin\] x \[fasting glucose x 0.055\]/22.5). The 78 week time point was added via a protocol amendment after study start. This is not a primary outcome, but rather a 6-month post-primary outcome follow-up measure. |
| Changes in Objectively Measured Energy Intake (EI) | Baseline, weeks 26, 52, and 78. | EI will be measured using the doubly-labeled water (DLW) intake-balance method. The 78 week time point was added via a protocol amendment after study start. This is not a primary outcome, but rather a 6-month post-primary outcome follow-up measure. |
| Changes in Self-Reported Energy Intake (EI) | Baseline and weeks 13, 26, 52, and 78. | Dietary energy intake (kcals/day) will be measured with diet diaries. The 78 week time point was added via a protocol amendment after study start. This is not a primary outcome, but rather a 6-month post-primary outcome follow-up measure. |
| Changes in Self-reported Diet Composition | Baseline and weeks 13, 26, 52, and 78. | Dietary macronutrient intake will be measured with diet diaries. The 78 week time point was added via a protocol amendment after study start. This is not a primary outcome, but rather a 6-month post-primary outcome follow-up measure. |
| Changes in Self-Reported Dietary Adherence | Weeks 4, 8, 13, 18, 22, 26, 30, 34, 39, 44, 48, 52 | Adherence to prescribed diet will be assessed with a monthly questionnaire. |
| Changes in Resting Energy Expenditure (REE) | Baseline and weeks 26, 52, and 78. | REE will be measured using indirect calorimetry. The 78 week time point was added via a protocol amendment after study start. This is not a primary outcome, but rather a 6-month post-primary outcome follow-up measure. |
| Changes in Total Daily Energy Expenditure (TDEE) | Baseline and weeks 26, 52, and 78. | TDEE will be measured using the doubly-labeled water (DLW) method. The 78 week time point was added via a protocol amendment after study start. This is not a primary outcome, but rather a 6-month post-primary outcome follow-up measure. |
| Changes in Physical Activity | Baseline and weeks 13, 26, 52, and 78. | Physical activity will be measured with activity monitors. The 78 week time point was added via a protocol amendment after study start. This is not a primary outcome, but rather a 6-month post-primary outcome follow-up measure. |
| Changes in Sedentary Behavior | Baseline and weeks 13, 26, 52, and 78. | Sedentary behavior will be measured with activity monitors. The 78 week time point was added via a protocol amendment after study start. This is not a primary outcome, but rather a 6-month post-primary outcome follow-up measure. |
Countries
United States
Contacts
PRINCIPAL_INVESTIGATORVictoria Catenacci, MD
University of Colorado Anschutz Health and Wellness Center
Outcome results
None listed