Comparison of Weight Loss Induced by Intermittent Fasting Versus Daily Caloric Restriction in Individuals With Obesity: A 1-Year Randomized Trial
Overview
- Phase
- Not Applicable
- Intervention
- Daily Caloric Restriction (DCR)
- Conditions
- Obesity
- Sponsor
- University of Colorado, Denver
- Enrollment
- 165
- Locations
- 1
- Primary Endpoint
- Change in Body Weight
- Status
- Completed
- Last Updated
- 2 months ago
Overview
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.
Investigators
Eligibility Criteria
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
- •Exclusion Criteria
- •Diastolic blood pressure \> 100 mm of Mercury (HG) or systolic blood pressure \> 160 mm HG.
- •Resting heart rate \>100
Arms & Interventions
Daily Caloric Restriction (DCR)
Participants in this group will focus on daily calorie restriction as their dietary weight loss strategy.
Intervention: Daily Caloric Restriction (DCR)
Intermittent Fasting (IMF)
Participants in this group will focus on modified intermittent fasting as their dietary weight loss strategy.
Intervention: Intermittent Fasting (IMF)
Outcomes
Primary Outcomes
Change in Body Weight
Time Frame: Baseline and weeks 4, 13, 26, 39, 52.
Body weight will be measured via clinic scale.
Secondary Outcomes
- Changes in Fasting Lipids(Baseline and weeks 26, 52, and 78.)
- Changes in Insulin Sensitivity(Baseline and weeks 26, 52, and 78.)
- Changes in Objectively Measured Energy Intake (EI)(Baseline, weeks 26, 52, and 78.)
- Changes in Physical Activity(Baseline and weeks 13, 26, 52, and 78.)
- Changes in Total Daily Energy Expenditure (TDEE)(Baseline and weeks 26, 52, and 78.)
- Changes in Blood Pressure(Baseline and weeks 13, 26, 52, and 78.)
- Changes in Resting Energy Expenditure (REE)(Baseline and weeks 26, 52, and 78.)
- Changes in Sedentary Behavior(Baseline and weeks 13, 26, 52, and 78.)
- Change in Body Weight(Week 78.)
- Changes in Body Composition(Baseline and weeks 26, 52, and 78.)
- Changes in Self-Reported Energy Intake (EI)(Baseline and weeks 13, 26, 52, and 78.)
- Changes in Self-Reported Dietary Adherence(Weeks 4, 8, 13, 18, 22, 26, 30, 34, 39, 44, 48, 52)
- Changes in Self-reported Diet Composition(Baseline and weeks 13, 26, 52, and 78.)