Intermittent Fasting for Obesity

(POWER-VET Trial)

Not currently recruiting at 1 trial location

Overseen By Kristina Marcus, MS

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: VA Office of Research and Development

Must not be taking: Insulin, Anti-coagulants

Disqualifiers: Diabetes, Autoimmune, Psychiatric, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: Unknown

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial aims to determine if intermittent fasting helps people maintain their weight more effectively than traditional methods. Participants will follow either a heart-healthy diet with exercise or the same plan with added intermittent fasting, which involves eating two small meals one day a week for 24 weeks. The study seeks veterans aged 50 to 75, who are postmenopausal (for women), and have a BMI (a measure of body fat based on height and weight) between 25 and 40. As an unphased study, this trial provides a unique opportunity to contribute to understanding new weight management strategies.

Will I have to stop taking my current medications?

The trial information does not specify if you need to stop taking your current medications. However, if you are on anti-coagulant medication, it may be relevant only for muscle biopsies.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research has shown that intermittent fasting is generally safe for people with obesity. In one study, participants reported no negative side effects, and there was no increase in low blood sugar episodes. Other studies have found that intermittent fasting can help people with obesity lose weight and improve heart health. Overall, it appears to be well-tolerated and could be a promising way to manage weight. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about the intermittent fasting approach for obesity because it introduces a unique regimen not typically seen in standard care options like reduced-calorie diets or medication. This method combines heart-healthy nutrition and regular exercise with intermittent fasting, specifically two small meals one day per week over 24 weeks. Unlike traditional approaches that often require daily calorie restriction, this intermittent model may offer a more sustainable and flexible lifestyle change, potentially leading to improved adherence and better long-term weight management.

What evidence suggests that this trial's treatments could be effective for obesity?

Research has shown that intermittent fasting can aid in weight loss. One study found that people who ate only during the early part of the day lost more weight and had better blood pressure than those who ate throughout the day. Another review found that intermittent fasting provides various health benefits for overweight or obese adults. Studies also indicate that intermittent fasting can lower body weight and boost metabolism. In this trial, participants will follow either a Weight Maintenance plan or a Weight Maintenance plan combined with Intermittent Fasting. Overall, intermittent fasting appears to offer similar weight loss benefits as regular dieting. ^{6 7 8 9 10}

Who Is on the Research Team?

Alice S. Ryan, PhD

Principal Investigator

Baltimore VA Medical Center VA Maryland Health Care System, Baltimore, MD

Are You a Good Fit for This Trial?

This trial is for veterans aged 50-75 with a BMI of 25-40, including postmenopausal women. It's not suitable for those who've had significant weight changes recently, are on blood thinners (for muscle biopsies), have impaired kidney function, serious liver disease, uncontrolled diabetes, or active major health conditions.

Inclusion Criteria

I am between 50 and 75 years old.

Your body mass index (BMI) is between 25 and 40, which means you are overweight or obese.

Veteran

Exclusion Criteria

You have a history of alcohol or drug abuse, as reported by yourself.

I have a condition that makes it hard for me to do physical tests.

I do not have active inflammatory, autoimmune, infectious, hepatic, gastrointestinal, malignant, or psychiatric diseases.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Weight Loss and Exercise

Participants undergo a weight loss and exercise program

12 weeks

Regular visits for monitoring and support

Weight Maintenance

Participants follow a weight maintenance program with or without intermittent fasting

24 weeks

Regular visits for monitoring and support

Follow-up

Participants are monitored for safety and effectiveness after the weight maintenance phase

12 weeks

Follow-up visits to assess long-term outcomes

What Are the Treatments Tested in This Trial?

Interventions

• Weight Maintenance
• Weight Maintenance + Intermittent Fasting

Trial Overview The study is testing traditional weight maintenance methods against the addition of intermittent fasting to see if it helps prevent weight regain after loss. The goal is to find cost-effective strategies for managing obesity in adults.

How Is the Trial Designed?

Group I: Weight Maintenance + Intermittent Fasting Experimental Treatment 1 Intervention

Heart Healthy nutrition, walking, resistance band exercise and intermittent fasting (2 small meals per day) one day per week for 24 weeks.

Group II: Weight Maintenance Active Control 1 Intervention

Heart Healthy nutrition, walking, resistance band exercise

Who Is Running the Clinical Trial?

VA Office of Research and Development

Lead Sponsor

Trials

1,691

Recruited

3,759,000+

South Texas Veterans Health Care System

Collaborator

Trials

19

Recruited

6,100+

Baltimore VA Medical Center

Collaborator

Trials

33

Recruited

3,000+

Baltimore Veterans Affairs Medical Center

Collaborator

Trials

5

Recruited

470+

Published Research Related to This Trial

Intermittent fasting (IF) may be an effective weight management strategy for overweight and obese adults, but its evidence base in humans is still limited, with only one published systematic review available.

Current guidelines from the National Institute for Health and Care Excellence (NICE) do not recommend very low calorie diets (VLCD) as a routine treatment for obesity, highlighting concerns about potential side effects and the sustainability of fasting approaches.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Intermittent fasting interventions for the treatment of overweight and obesity in adults aged 18 years and over: a systematic review protocol. Jane, L., Atkinson, G., Jaime, V., et al.[2022]

In a 10-week study with 16 obese participants, alternate day modified fasting (ADMF) led to an average weight loss of 5.6 kg, demonstrating its effectiveness as a weight loss strategy.

Participants adapted well to ADMF, with significant reductions in energy intake on fasting days and no increase in hunger, while maintaining physical activity levels, suggesting that dietary and activity adaptations contribute to the weight loss observed.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Dietary and physical activity adaptations to alternate day modified fasting: implications for optimal weight loss. Klempel, MC., Bhutani, S., Fitzgibbon, M., et al.[2021]

Intermittent energy restriction, which includes methods like alternate day fasting, was found to be more effective than no treatment for weight loss in overweight and obese adults, with an average loss of 4.14 kg over the study period.

However, when compared to continuous energy restriction, intermittent energy restriction did not show a significant difference in weight loss, indicating that both approaches may be similarly effective for short-term weight management.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Intermittent fasting interventions for treatment of overweight and obesity in adults: a systematic review and meta-analysis. Harris, L., Hamilton, S., Azevedo, LB., et al.[2022]

Intermittent energy restriction (IER) strategies, such as intermittent fasting and time-restricted feeding, show similar effectiveness in weight loss compared to continuous energy restriction (CER) in adults with obesity, based on a review of randomized trials lasting at least 8 weeks.

Out of 11 studies analyzed, 9 found no significant differences in weight or body fat loss between IER and CER, suggesting that IER can be a viable alternative for obesity treatment.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effectiveness of Intermittent Fasting and Time-Restricted Feeding Compared to Continuous Energy Restriction for Weight Loss. Rynders, CA., Thomas, EA., Zaman, A., et al.[2021]

In an 8-week study with 59 obese participants, alternate day fasting (ADF) led to a significant weight loss of 4.2%, while only a small percentage reported mild adverse effects like constipation and dizziness.

ADF was associated with improvements in eating disorder symptoms, including a decrease in depression and binge eating, suggesting that it may have beneficial effects on body image and eating behaviors.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety of alternate day fasting and effect on disordered eating behaviors. Hoddy, KK., Kroeger, CM., Trepanowski, JF., et al.[2018]

Modified alternate-day fasting (ADF) led to significant weight loss (5.6 kg) and reduced body fat percentage in 16 obese adults over 8 weeks, demonstrating its efficacy as a weight management strategy.

ADF also improved cardiovascular health indicators, with notable reductions in total cholesterol, LDL cholesterol, and triglycerides, suggesting it may lower the risk of coronary artery disease.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Short-term modified alternate-day fasting: a novel dietary strategy for weight loss and cardioprotection in obese adults. Varady, KA., Bhutani, S., Church, EC., et al.[2023]

Citations

1. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/35939311/

Effectiveness of Early Time-Restricted Eating for Weight Loss ... Main outcomes and measures: The co-primary outcomes were weight loss and fat loss. Secondary outcomes included blood pressure, heart rate, ...

2. jamanetwork.com jamanetwork.com/journals/jamainternalmedicine/fullarticle/2794819

Effectiveness of Early Time-Restricted Eating for Weight ... In this randomized clinical trial, eTRE was more effective for losing weight and improving diastolic blood pressure and mood than eating over a window of 12 or ...

3. sciencedirect.com sciencedirect.com/science/article/pii/S2589537024000981

Intermittent fasting and health outcomes: an umbrella ... Our findings suggest that IF may have beneficial effects on a range of health outcomes for adults with overweight or obesity, compared to CER or non- ...

4. nutritionj.biomedcentral.com nutritionj.biomedcentral.com/articles/10.1186/s12937-025-01178-6

The impact of intermittent fasting on body composition and ... Numerous studies have shown [18,19,20,21] that intermittent fasting can not only effectively reduce body weight but also improve metabolic ...

5. bmj.com bmj.com/content/389/bmj-2024-082007

Intermittent fasting strategies and their effects on body ... The current evidence provides some indication that intermittent fasting diets have similar benefits to continuous energy restriction for weight loss and ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC8683964/

Intermittent Fasting and Obesity-Related Health Outcomes Outcomes associated with modified alternate-day fasting included a moderate reduction of body weight, body mass index, and cardiometabolic risk ...

7. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC10945168/

Intermittent fasting and health outcomes: an umbrella ... Our findings suggest that IF may have beneficial effects on a range of health outcomes for adults with overweight or obesity, compared to CER or ...

8. bmcendocrdisord.biomedcentral.com bmcendocrdisord.biomedcentral.com/articles/10.1186/s12902-025-01952-x

Effect of intermittent fasting on obesity and metabolic indices ... It has been shown to be associated with a twofold increased risk of cardiovascular events and numerous endocrine disorders. Energy restriction ...

9. sciencedirect.com sciencedirect.com/science/article/abs/pii/S2451847618300290

The safety and efficacy of weight loss via intermittent ... There were no adverse events during the study, and rates of hypoglycaemia were unchanged. Body weight was reduced from baseline (P < 0.05) by both intermittent ...

10. hopkinsmedicine.org hopkinsmedicine.org/health/wellness-and-prevention/intermittent-fasting-what-is-it-and-how-does-it-work

Intermittent Fasting: What is it, and how does it work? In animal studies, intermittent fasting prevented obesity. And, in six brief studies, obese adult humans lost weight through intermittent fasting.