Diets for Reducing Abdominal Fat in Obesity

((HDLS2) Trial)

Overseen By Carol J Boushey, PhD, RDN

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of Hawaii

Must not be taking: Anti-estrogens, Anti-androgens, Insulin

Disqualifiers: Pregnancy, Diabetes, Thyroid conditions, others

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

Compensation: Varies

Number of Visits: 6

Duration: 24 weeks

260 Participants Needed

Trial Summary

What is the purpose of this trial?

This trial tests a diet where people eat much less for a few days and follow a healthy Mediterranean diet for the rest of the time. It targets middle-aged adults from specific ethnic groups with high levels of harmful fat. The goal is to encourage the body to burn more fat, especially around the belly and liver.

Will I have to stop taking my current medications?

The trial does not specify if you need to stop taking your current medications. However, if you are taking anti-estrogen or anti-androgen medications, or insulin for diabetes, you may not be eligible to participate.

What data supports the effectiveness of the treatment IER+MED for reducing abdominal fat in obesity?

Research shows that intermittent energy restriction (IER) is an effective strategy for managing obesity, producing weight loss comparable to continuous energy restriction (CER). Additionally, the Mediterranean diet is known for its health benefits, including weight management, which suggests that combining IER with a Mediterranean diet could be effective for reducing abdominal fat. ^{1 2 3 4 5}

Is the combination of intermittent energy restriction and a Mediterranean diet safe for humans?

Research indicates that combining intermittent energy restriction with a Mediterranean diet is generally safe for humans, with no major adverse effects reported in studies. Participants adhered well to the diet, and it was found to be acceptable and effective in reducing body fat and improving liver function. ^{1 6 7 8 9}

How is the IER+MED treatment different from other treatments for reducing abdominal fat in obesity?

The IER+MED treatment combines intermittent energy restriction (IER), which involves alternating periods of eating less with normal eating, with the Mediterranean diet, known for its heart-healthy ingredients like olive oil, fruits, and vegetables. This approach is unique because it merges the benefits of intermittent fasting with the nutritional advantages of the Mediterranean diet, potentially offering a more sustainable and effective way to reduce abdominal fat compared to traditional continuous calorie restriction. ^{1 6 9 10 11}

Research Team

Loic Le Marchand, MD, PhD

Principal Investigator

University of Hawaii Cancer Research Center

Eligibility Criteria

Adults aged 35-69 with a BMI of 25-40 and abdominal obesity (VAT ≥90 cm2 for men, ≥80 cm2 for women), who are non-smokers, drink little alcohol, have no serious health issues or recent substantial weight changes. Must be East Asian, Native Hawaiian/Pacific Islander or White ethnicity and fully vaccinated against COVID-19.

Inclusion Criteria

DXA VAT ≥90 cm2 for men and ≥80 cm2 for women

I have taken antibiotics in the last 3 months.

Fully vaccinated for COVID-19

Exclusion Criteria

I have diabetes and am on insulin treatment.

I cannot walk for up to an hour each day.

Contraindication to MR imaging (e.g. pacemaker, claustrophobia, metal implants)

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants follow either the IER+MED or MED/DER diet plan for 24 weeks, with dietary and physical activity counseling sessions.

24 weeks

4 in-person visits, 12 remote meetings

Follow-up

Participants are monitored for long-term effects on body weight and adiposity, including DXA scans and BMI measurements.

24 weeks

2 visits (in-person)

Treatment Details

Interventions

• IER+MED
• MED/DER

Trial Overview The study is testing whether combining Intermittent Energy Restriction (IER) with the Mediterranean diet (MED) is more effective than daily energy restriction (DER) with MED in reducing belly fat and improving cancer-related markers over six months.

Participant Groups

Group I: Mediterranean diet (MED) + daily energy restriction (DER) or MED/DER Experimental Treatment 1 Intervention

The MED/DER group intervention will restrict 20% energy (25%, 45% and 30% distribution of protein, carbohydrate, and fat, respectively) continuously. Participants will also be asked to follow a moderate exercise program (1 hour of walking five days a week).

Group II: Intermittent energy restriction (IER) + Mediterranean diet (MED) or IER+MED Experimental Treatment 1 Intervention

The IER+MED group intervention will be to restrict 70% energy (25%, 45% and 30% distribution of protein, carbohydrate, and fat, respectively) on 2 days and follow a MED diet (25%, 45%, 30%) and meet their estimated energy requirement (EER) for the other 5 days each week. This would be equivalent to an over-all 20% daily energy restriction. Participants will also be asked to follow a moderate exercise program (1 hour of walking five days a week).

Who Is Running the Clinical Trial?

University of Hawaii

Lead Sponsor

Trials

122

Recruited

55,200+

National Institutes of Health (NIH)

Collaborator

Trials

2,896

Recruited

8,053,000+

University of Hawaii Cancer Research Center

Collaborator

Trials

11

Recruited

2,100+

National Cancer Institute (NCI)

Collaborator

Trials

14,080

Recruited

41,180,000+

Findings from Research

Intermittent energy restriction (IER) was found to be a feasible and effective weight management strategy for adolescents aged 12-17 with obesity, leading to a significant reduction in BMI %95th percentile after 12 weeks (-5.6%) and maintained reductions at 26 weeks.

Participants reported IER as easy and pleasant to follow, indicating high acceptability, and the intervention also resulted in improvements in cardiovascular health markers, such as reduced carotid intima-media thickness and improved flow-mediated dilation.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Intermittent Energy Restriction Is a Feasible, Effective, and Acceptable Intervention to Treat Adolescents with Obesity. Jebeile, H., Gow, ML., Lister, NB., et al.[2023]

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 a 2-week study with 16 healthy-weight participants, both intermittent energy restriction (IER) and continuous energy restriction (CER) resulted in similar weight loss, around 2.5 kg, indicating that IER can be as effective as CER for weight reduction.

While there were no significant differences in post-meal insulin or blood glucose levels between the two diets, IER led to lower fasting blood glucose levels and improved appetite ratings, suggesting potential metabolic benefits of IER beyond just weight loss.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effects of intermittent (5:2) or continuous energy restriction on basal and postprandial metabolism: a randomised study in normal-weight, young participants. Gao, Y., Tsintzas, K., Macdonald, IA., et al.[2022]

Intermittent energy restriction (IER) and continuous energy restriction (CER) both effectively improved metabolic syndrome (MetS) risk factors, but IER showed a significant advantage in increasing HDL cholesterol levels compared to CER.

In terms of secondary outcomes, IER led to greater reductions in body weight, body fat, and fat-free mass compared to CER, indicating that IER may be a more effective approach for weight management in individuals with MetS.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Intermittent energy restriction vs. continuous energy restriction on cardiometabolic risk factors in patients with metabolic syndrome: a meta-analysis and systematic review. Xu, R., Cao, Y., Wang, PY., et al.[2023]

Intermittent energy restriction (IER) is as effective as continuous energy restriction for weight loss in overweight and obese individuals, with some studies showing greater reductions in body fat and insulin resistance without significant harm.

The long-term effects of IER on health and body composition, especially in normal weight individuals, remain unclear and require further research to determine potential benefits or risks.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Potential Benefits and Harms of Intermittent Energy Restriction and Intermittent Fasting Amongst Obese, Overweight and Normal Weight Subjects-A Narrative Review of Human and Animal Evidence. Harvie, M., Howell, A.[2022]

A 12-week pilot study involving 60 East Asian participants showed that the Intermittent Energy Restriction combined with a Mediterranean diet (IER+MED) led to significantly greater reductions in visceral adipose tissue (VAT) and total fat mass compared to the DASH diet.

While both diets improved liver function, IER+MED resulted in a more significant decrease in alanine transaminase levels, indicating better liver health, with a low attrition rate of 10% and no major adverse effects reported.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effects of Intermittent Energy Restriction Combined with a Mediterranean Diet on Reducing Visceral Adiposity: A Randomized Active Comparator Pilot Study. Panizza, CE., Lim, U., Yonemori, KM., et al.[2023]

Intermittent energy restriction (IER) and continuous energy restriction resulted in similar weight loss outcomes, with no significant differences in weight loss or body composition after 8-24 weeks across 11 trials.

IER showed a slight reduction in fasting insulin levels, but the clinical significance of this finding is uncertain, indicating that both dietary approaches may be effective for weight management and metabolic health.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Intermittent versus continuous energy restriction on weight loss and cardiometabolic outcomes: a systematic review and meta-analysis of randomized controlled trials. Cioffi, I., Evangelista, A., Ponzo, V., et al.[2020]

Intermittent energy restriction (IER) led to significant weight loss in overweight and obese adults, averaging about 0.2-0.8 kg per week, and was found to be as effective as daily energy restriction (DER) when total energy intake was similar.

Most studies indicated that IER was equally effective as DER in reducing fat mass, fat-free mass, and waist circumference, suggesting it could be a viable alternative weight-loss strategy for health practitioners.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Intermittent energy restriction and weight loss: a systematic review. Davis, CS., Clarke, RE., Coulter, SN., et al.[2022]

Intermittent energy restriction (IER) diets, such as alternate-day fasting and time-restricted feeding, are effective for weight loss and can improve metabolic health markers like blood pressure, lipid levels, and glucose control.

IER diets are as effective as continuous energy restriction diets for weight loss, making them a viable alternative for individuals who struggle with constant calorie restriction.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The Role of Intermittent Energy Restriction Diet on Metabolic Profile and Weight Loss among Obese Adults. Stanek, A., Brożyna-Tkaczyk, K., Zolghadri, S., et al.[2022]

In a one-year study involving 332 overweight and obese adults, intermittent energy restriction (IER) methods (week-on-week-off and 5:2) resulted in similar weight loss and body composition changes as continuous energy restriction (CER), with mean weight losses of -6.6 kg for CER, -5.1 kg for week-on-week-off, and -5.0 kg for 5:2.

All three dietary approaches led to improvements in HDL-cholesterol and triglycerides, but there were no significant differences in these outcomes or in fasting glucose and LDL-cholesterol levels among the groups.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effect of intermittent compared to continuous energy restriction on weight loss and weight maintenance after 12 months in healthy overweight or obese adults. Headland, ML., Clifton, PM., Keogh, JB.[2021]

References

1. United States pubmed.ncbi.nlm.nih.gov

Intermittent Energy Restriction Is a Feasible, Effective, and Acceptable Intervention to Treat Adolescents with Obesity. [2023]

2. Australia pubmed.ncbi.nlm.nih.gov

Intermittent fasting interventions for treatment of overweight and obesity in adults: a systematic review and meta-analysis. [2022]

3. Switzerland pubmed.ncbi.nlm.nih.gov

Effectiveness of Intermittent Fasting and Time-Restricted Feeding Compared to Continuous Energy Restriction for Weight Loss. [2021]

4. England pubmed.ncbi.nlm.nih.gov

Effects of intermittent (5:2) or continuous energy restriction on basal and postprandial metabolism: a randomised study in normal-weight, young participants. [2022]

5. Switzerland pubmed.ncbi.nlm.nih.gov

Intermittent energy restriction vs. continuous energy restriction on cardiometabolic risk factors in patients with metabolic syndrome: a meta-analysis and systematic review. [2023]

6. Switzerland pubmed.ncbi.nlm.nih.gov

Potential Benefits and Harms of Intermittent Energy Restriction and Intermittent Fasting Amongst Obese, Overweight and Normal Weight Subjects-A Narrative Review of Human and Animal Evidence. [2022]

7. Switzerland pubmed.ncbi.nlm.nih.gov

Effects of Intermittent Energy Restriction Combined with a Mediterranean Diet on Reducing Visceral Adiposity: A Randomized Active Comparator Pilot Study. [2023]

8. England pubmed.ncbi.nlm.nih.gov

Intermittent versus continuous energy restriction on weight loss and cardiometabolic outcomes: a systematic review and meta-analysis of randomized controlled trials. [2020]

9. England pubmed.ncbi.nlm.nih.gov

Intermittent energy restriction and weight loss: a systematic review. [2022]

10. Switzerland pubmed.ncbi.nlm.nih.gov

The Role of Intermittent Energy Restriction Diet on Metabolic Profile and Weight Loss among Obese Adults. [2022]

11. England pubmed.ncbi.nlm.nih.gov

Effect of intermittent compared to continuous energy restriction on weight loss and weight maintenance after 12 months in healthy overweight or obese adults. [2021]