Longitudinal Monitoring During Intermittent Fasting Protocols in Obese Adults (LIMITFOOD2)

Longitudinal Monitoring During Different Intermittent Fasting Protocols in Obese Adults - A Randomized Clinical Trial

LIMITFOOD2 is a randomized clinical intervention study that investigates the effects of two different intermittent fasting protocols compared to a control group on the health of obese adults. A total of 90 participants will be randomized into three equally sized groups: a modified alternate day fasting, a time-restricted eating and a control group, receiving general weight-loss counseling.

Study Overview

• Status: Not yet recruiting
• Conditions: Obesity; Intermittent Fasting; Time Restricted Eating
• Intervention / Treatment: Behavioral: Modified Alternate Day Fasting; Behavioral: Time-Restricted Eating; Behavioral: Weight-loss counseling

Detailed Description

The prevalence of overweight and obesity worldwide has risen considerably in the past century with more than one billion overweight persons, and about 600 million obese patients in 2015. Humans in modern societies typically eat at least three main meals per day and snacks around the clock. This change in eating pattern in terms of quantity and frequency leads to overconsumption of food and consequently to excess weight. Furthermore, obesity increases the risk of developing diabetes, cardiovascular disease and several types of cancer. The world health organization (WHO) has stated that there are 2.8 million deaths per year as a result of overweight and obesity.

In recent years, the concept of re-introduced fasting intervals in the form of intermittent fasting (IF) protocols became a popular alternative dietary strategy with the aim to achieve weight control and improve metabolic health. There are several different IF protocols, the most popular is time-restricted eating (TRE), which allows ad libitum (at one's pleasure) energy intake within a defined time period each time (6 to 12 hours). Another IF protocol is alternate day fasting (ADF), on 'feast days' one can consume food ad libitum, while on 'fast days' no or little food is consumed, feast and fast days alternate throughout the week. Animal studies and previous human clinical trials have provided evidence that various types of IF lead to weight loss and improved health markers. So far, interventional studies focused on the comparison of IF versus a control group, however only few studies compared different IF protocols directly. Given both the evidence for beneficial effects of IF as well as its growing popularity, it seems mandatory to reveal possible differences in the effectiveness of different protocols.

The present project will allow to directly compare two types of IF with each other and with a control group in obese participants. Furthermore, established and novel monitoring tools to track individual progress during IF are scarcely used so far but may become an important help in the future and thus, will be implemented in this trial.

• Study Type: Interventional
• Enrollment (Estimated): 90
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Johanna Zehnder, MSc; Phone Number: +41432532409; Email: johanna.zehnder@usz.ch

Study Locations

• Switzerland
  • Zürich, Switzerland, 8091
    • Department of Endocrinology, Diabetology and Clinical Nutrition

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Age between 18-50 years, both inclusive
• Obese, BMI between 30 and 40 kg/m^2 (obesity grade I or II), both inclusive
• Non-smoker
• Good knowledge of German or English language
• Stable weight change (change < +/- 3% current bodyweight) for 3 months prior to the study
• HbA1c < 6.5% without glucose lowering medication
• LDL-cholesterol < 4.6mmol/l without lipid lowering medication

Exclusion Criteria:

• Participants who have a fasting period of > 12h per day on a regular basis and do not eat at least three main meals per day.
• Current habitual use of dietary supplements (e.g., vitamins, minerals) and/or unwillingness to cease intake of dietary supplements.
• Antibiotics intake during 3 months prior to the study due to possible interference with metabolic parameters
• Food intolerances, allergies and sensitivities (severe food allergies) or dietary restrictions (e.g. vegan lifestyle)
• Acute or chronic infections, malignant disease, renal, hepatic (more than two-fold increased transaminases), pulmonary, neurological (epilepsy) or psychiatric diseases, manifested atherosclerosis, or any other disease precluding participation in the study.
• Diabetes
• Known alcohol, substance or drug abuse, concomitant medication
• More than four hours of physical exercise per week
• Women who are pregnant, breast-feeding or aiming to become pregnant during course of the trial
• Women and men on hormonal supplementation
• Women with an irregular menstrual cycle according to the FIGO criteria
• Therapy with antidepressants within the past 6 months
• Regular therapy with acetylsalicyclic acid or current medication to regulate blood sugar, blood pressure or lipids
• Participants likely to fail to comply with the study protocol
• Participants who do not give informed consent

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Modified Alternate Day Fasting (mADF); Participants in the mADF group will be instructed to eat every second-day ad libitum ("feast days"), and to consume a very low carbohydrate snack, restricted to the evening, provided by the study team and to otherwise abstain from calorie intake on the rest of the fast day.	Behavioral: Modified Alternate Day Fasting; Participants are instructed to fast every other day.
Active Comparator: Time-Restricted Eating (TRE); TRE participants are instructed to eat two main meals and limit snacking from 12:00 to 20:00 daily, and to fast from 20:00 until 12:00 daily	Behavioral: Time-Restricted Eating; Participants are instructed to limit food intake to two main meals consumed in maximum 8 hours per day
Other: Control group; The control group will receive guidance on a quantitative reduction in total caloric intake by following a balanced diet, but no timing window for food intake will be prescribed to the participants in the control group.	Behavioral: Weight-loss counseling; Participants will receive nutrition counseling to structure their main meals according to the plate model for weight-loss and to reduce number of consumed plates.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Fat Volume	Change in body fat volume measured with MRI	8 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Distribution of fat volume	Changes in subcutaneous and visceral fat volume measured with MRI	8 weeks
Concentration of Leptin	Change in leptin concentrations will be measured.	8 weeks
Changes in Inflammatory Markers	Changes in concentration of C-reactive protein and Interleukin-1beta will be measured.	8 weeks
Free triiodothyronine (fT3)	Change in serum levels of fT3 will be measured.	8 weeks
Changes in Insulin Sensitivity	Insulin Sensitivity will be assessed using the homeostasis model assessment of insulin resistance (HOMA-IR), which is calculated from insulin and glucose concentration from a 12 hours fasting blood sample.	8 weeks
Changes in Fasting Lipids	Changes in concentration of Apolipoprotein B and triglycerides will be measured from a 12 hours fasting blood sample.	8 weeks

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Correlation of longitudinally measured parameters	Breath acetone measurements and continuous glucose monitoring will be conducted and correlated to the fat volume change.	8 weeks
Serum Metabolomics	Metabolomics provides an insight into the organisms current metabolite profile. Exploring the effect of intermittent fasting on specific metabolites could provide important insights.	8 weeks
Genetic Analysis	Genes associated with obesity could have an effect on the efficacy of the intermittent fasting intervention and genetic analysis may provide an important step towards personalized medicine.	8 weeks
LDL Particle Size	Changes in serum LDL particle size might be measured.	8 weeks
Fecal Microbiome	Sequencing will be used to identify the composition of bacteria and archaea within the fecal samples. Exploring the changes in the microbiome induced by intermittent fasting could provide valuable insights.	8 weeks

Collaborators and Investigators

• Sponsor: University of Zurich
• Investigators: Principal Investigator: Philipp Gerber, MD, University of Zurich

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2024
• Primary Completion (Estimated): January 1, 2026
• Study Completion (Estimated): January 1, 2027

Study Registration Dates

• First Submitted: March 6, 2024
• First Submitted That Met QC Criteria: March 14, 2024
• First Posted (Actual): March 21, 2024

Study Record Updates

• Last Update Posted (Actual): April 19, 2024
• Last Update Submitted That Met QC Criteria: April 16, 2024
• Last Verified: April 1, 2024

More Information

Terms related to this study

• Keywords: Obesity; Body Weight; Nutrition Disorders; Overnutrition; Longitudinal monitoring
• Additional Relevant MeSH Terms: Overnutrition; Nutrition Disorders; Overweight; Body Weight; Obesity
• Other Study ID Numbers: LIMITFOOD2

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No