Intermittent Fasting, Body Weight, and Body CompositionIF-ANTHRONCT07912255
Intermittent Fasting and Anthropometric Parameters
A study testing Intermittent Fasting with Energy Restriction, Energy Restriction without Intermittent Fasting and Intermittent Fasting without Energy Restriction in people with Intermittent Fasting, Body Weight, and Body Composition, run by Masaryk University at 1 site in Czechia.
Trial summary
This study examined whether intermittent fasting helps people lose weight and body fat, and whether it affects muscle mass. The researchers compared intermittent fasting with a diet that reduced daily energy intake without limiting meal times. The study included healthy adult volunteers aged over 18 years. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Intermittent Fasting, Body Weight, and Body Composition
- What is being tested?
- Intermittent Fasting with Energy Restriction, Energy Restriction without Intermittent Fasting and Intermittent Fasting without Energy Restriction
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 95 participants
- Where
- 1 siteCzechia
- Study dates
- 12 Apr 2023to 3 Jul 2023
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Adults aged over 18 years. Interest in and willingness to spend time preparing and consuming meals according to the prescribed dietary plan.
Who cannot join
- Pregnancy or breastfeeding. Presence of a pacemaker or insulin pump. Underweight (BMI < 18.5 kg/m²). Cancer, gout, severe gastrointestinal disease, kidney disease, diabetes mellitus, autoimmune disease, thyroid disease, or eating disorders.
- History of organ transplantation. Use of warfarin. Inability to consume the prescribed foods, including adherence to a vegan diet.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: The Influence of Intermittent Fasting on Selected Human Anthropometric Parameters
This study examined whether intermittent fasting helps people lose weight and body fat, and whether it affects muscle mass. The researchers compared intermittent fasting with a diet that reduced daily energy intake without limiting meal times.
The study included healthy adult volunteers aged over 18 years. Researchers randomly assigned 95 participants to one of three groups. The dietary intervention lasted three weeks, and 75 participants completed it.
Read more
Participants followed one of these eating plans:
Intermittent fasting with reduced energy intake: Participants ate 25% less energy than their estimated daily needs. They ate all their meals within a six-hour period each day.
Reduced energy intake without intermittent fasting: Participants ate 25% less energy than their estimated daily needs. They could eat throughout the day without a fixed eating window.
Intermittent fasting without reduced energy intake: Participants ate enough energy to meet their estimated daily needs. They ate all their meals within a six-hour period each day.
Researchers measured body weight and body composition before and after the intervention. They used a body composition analyzer to estimate body fat, muscle mass, and other body tissues. They also contacted participants weekly to monitor their progress and any problems related to the diet.
After three weeks, participants in the first group lost an average of 2.3 kilograms of body weight. Those in the second group lost 2.2 kilograms. The difference between these groups was not statistically significant. Participants in the third group lost an average of 1.1 kilograms, which was significantly less than in the other two groups.
All three groups lost some body fat. However, the differences in body fat loss between the groups were not statistically significant. The group combining intermittent fasting with reduced energy intake showed a greater loss of fat-free mass than the group practicing intermittent fasting without reducing energy intake.
The results suggest that reducing daily energy intake was more important for short-term weight loss than limiting meal times alone. Longer studies are needed to determine the lasting effects of these eating patterns on body weight and body composition.
Read the detailed description
Intermittent fasting is an eating pattern in which people consume food only during a defined period of the day. It may help with weight loss, but it is unclear whether limiting eating hours provides additional benefits when daily energy intake is reduced. Another concern is whether intermittent fasting leads to a greater loss of muscle mass during weight loss.
The aim of this study was to compare intermittent fasting with continuous energy restriction. The researchers examined changes in body weight and body composition. They also investigated the effects of intermittent fasting without a prescribed reduction in daily energy intake.
This randomized controlled study included three dietary intervention groups. A total of 95 participants were randomly assigned to the groups, and 75 completed the three-week intervention. Participants were healthy adult volunteers older than 18 years. People with medical conditions that could make participation unsafe or affect the results were excluded.
Study groups and dietary interventions
Participants received an individual meal plan based on their estimated daily energy needs and usual physical activity.
Intermittent fasting with energy restriction: Participants consumed 75% of their estimated daily energy needs within a six-hour eating window. They fasted for the remaining 18 hours.
Continuous energy restriction: Participants consumed 75% of their estimated daily energy needs without a prescribed eating window.
Intermittent fasting without energy restriction: Participants consumed 100% of their estimated daily energy needs within a six-hour eating window. They fasted for the remaining 18 hours.
Participants selected the start of their six-hour eating window according to their daily routine. All groups followed meal plans designed to provide adequate nutrients. The plans emphasized sufficient protein and dietary fiber, along with vegetables, fruit, whole grains, dairy products, and other sources of protein. Participants could drink water, unsweetened tea, and unsweetened coffee. They were instructed to leave at least three hours between their last food intake and bedtime.
Researchers contacted participants by telephone during the intervention to monitor adherence to the meal plans and identify possible adverse events.
Measurements and outcomes
Researchers measured body weight, height, waist circumference, and other body measurements before and after the intervention. They assessed body composition using multifrequency bioelectrical impedance analysis. This method estimates body fat, fat-free mass, skeletal muscle mass, and other body compartments by measuring the body's response to a weak electrical current.
The main outcomes were changes in body weight and body composition after three weeks. Researchers also recorded adverse events, including fatigue, hunger, headaches, difficulties with concentration, and uncomfortable fullness after meals.
Main findings
Participants who followed intermittent fasting with energy restriction lost an average of 2.3 kilograms. Participants who followed continuous energy restriction lost an average of 2.2 kilograms. The difference between these groups was not statistically significant.
Participants who followed intermittent fasting without energy restriction lost an average of 1.1 kilograms. Their weight loss was significantly smaller than that of the other two groups.
The groups did not differ significantly in the amount of body fat lost. The group combining intermittent fasting with energy restriction lost more fat-free mass than the group practicing intermittent fasting without energy restriction. The difference between these groups was statistically significant. However, the study did not find a statistically significant difference in fat-free mass loss between intermittent fasting with energy restriction and continuous energy restriction.
No serious adverse events were reported. Fatigue was more frequent in the group combining intermittent fasting with energy restriction than in the continuous energy restriction group. Uncomfortable fullness or overeating was more frequent in the group practicing intermittent fasting without energy restriction than in the continuous energy restriction group.
Conclusion
The study found that intermittent fasting combined with reduced energy intake did not lead to significantly greater weight loss or body fat loss than continuous energy restriction over three weeks. Limiting eating hours without reducing prescribed energy intake resulted in less weight loss. The findings suggest that both energy intake and diet quality are important when considering changes in body weight and body composition.
The study was limited by its short duration and relatively small number of participants. Body composition was assessed using bioelectrical impedance analysis rather than dual-energy X-ray absorptiometry. Further research is needed to determine the long-term effects of these eating patterns.
- Being tested
- Intermittent Fasting with Energy Restriction, Energy Restriction without Intermittent Fasting, Intermittent Fasting without Energy Restriction
- Keywords
- Intermittent fasting, Time-restricted eating, Energy restriction, Weight loss, Body composition, Bioelectrical impedance analysis
- Medical subject headings
- Intermittent Fasting, Body Weight, Weight Loss
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Intermittent Fasting with Energy RestrictionBehavioural
Participants followed a six-hour daily eating window and consumed 75% of their estimated daily energy requirements for three weeks.
Energy Restriction without Intermittent FastingBehavioural
Participants consumed 75% of their estimated daily energy requirements for three weeks, without a prescribed six-hour eating window.
Intermittent Fasting without Energy RestrictionBehavioural
Participants followed a six-hour daily eating window and consumed 100% of their estimated daily energy requirements for three weeks.
| Study group | Role | What they receive |
|---|---|---|
| Intermittent Fasting with Energy Restriction | Experimental | Participants followed a six-hour daily eating window and consumed 75% of their estimated daily energy requirements for three weeks. Receives: Behavioral: Intermittent Fasting with Energy Restriction |
| Energy Restriction without Intermittent Fasting | Active comparator | Participants consumed 75% of their estimated daily energy requirements for three weeks, without a prescribed six-hour eating window. Receives: Behavioral: Energy Restriction without Intermittent Fasting |
| Intermittent Fasting without Energy Restriction | Experimental | Participants followed a six-hour daily eating window and consumed 100% of their estimated daily energy requirements for three weeks. Receives: Behavioral: Intermittent Fasting without Energy Restriction |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Body Weight
Change in body weight (kg) from baseline to the end of the three-week dietary intervention. Body weight was measured before and after the intervention, and the changes were compared between the three intervention groups.
Measured: Baseline and after 3 weeks of dietary intervention
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Nov 2026
- Study start12 Apr 2023
- Primary completion30 May 2023
- Study completion3 Jul 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Intermittent Fasting, Body Weight, and Body CompositionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 95 participants (actual)
Sponsor and investigators
- Lead sponsor
- Masaryk University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07912255
- Sponsor's protocol ID
- IF_MU_2022
- Acronym
- IF-ANTHRO
- Status last verified
- Oct 2026
- First submitted
- 27 Oct 2026
- Last updated
- 3 Nov 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Cermakova E, Forejt M, Cermak M. The Influence of Intermittent Fasting on Selected Human Anthropometric Parameters. Int J Med Sci. 2024 Oct 7;21(14):2630-2639. doi: 10.7150/ijms.99116. eCollection 2024.
PubMed 39512696
Study at a glance
From the registry record, last updated by the sponsor on 3 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Influence of Intermittent Fasting on Selected Human Anthropometric Parameters
- ClinicalTrials.gov ID
- NCT07912255
- Acronym / sponsor ID
- IF-ANTHRO / IF_MU_2022
- Keywords
- Intermittent fasting, Time-restricted eating, Energy restriction, Weight loss, Body composition, Bioelectrical impedance analysis
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 95 participants (actual)
- Lead sponsor
- Masaryk UniversityUniversity, hospital or other
- Study start
- 12 Apr 2023 (actual)
- Primary completion
- 30 May 2023 (actual)
- Study completion
- 3 Jul 2023 (actual)
- First posted
- 3 Nov 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study examined whether intermittent fasting helps people lose weight and body fat, and whether it affects muscle mass. The researchers compared intermittent fasting with a diet that reduced daily energy intake without limiting meal times.
The study included healthy adult volunteers aged over 18 years. Researchers randomly assigned 95 participants to one of three groups. The dietary intervention lasted three weeks, and 75 participants completed it.
Participants followed one of these eating plans:
Intermittent fasting with reduced energy intake: Participants ate 25% less energy than their estimated daily needs. They ate all their meals within a six-hour period each day.
Reduced energy intake without intermittent fasting: Participants ate 25% less energy than their estimated daily needs. They could eat throughout the day without a fixed eating window.
Intermittent fasting without reduced energy intake: Participants ate enough energy to meet their estimated daily needs. They ate all their meals within a six-hour period each day.
Researchers measured body weight and body composition before and after the intervention. They used a body composition analyzer to estimate body fat, muscle mass, and other body tissues. They also contacted participants weekly to monitor their progress and any problems related to the diet.
After three weeks, participants in the first group lost an average of 2.3 kilograms of body weight. Those in the second group lost 2.2 kilograms. The difference between these groups was not statistically significant. Participants in the third group lost an average of 1.1 kilograms, which was significantly less than in the other two groups.
All three groups lost some body fat. However, the differences in body fat loss between the groups were not statistically significant. The group combining intermittent fasting with reduced energy intake showed a greater loss of fat-free mass than the group practicing intermittent fasting without reducing energy intake.
The results suggest that reducing daily energy intake was more important for short-term weight loss than limiting meal times alone. Longer studies are needed to determine the lasting effects of these eating patterns on body weight and body composition.
Detailed description
Intermittent fasting is an eating pattern in which people consume food only during a defined period of the day. It may help with weight loss, but it is unclear whether limiting eating hours provides additional benefits when daily energy intake is reduced. Another concern is whether intermittent fasting leads to a greater loss of muscle mass during weight loss.
The aim of this study was to compare intermittent fasting with continuous energy restriction. The researchers examined changes in body weight and body composition. They also investigated the effects of intermittent fasting without a prescribed reduction in daily energy intake.
This randomized controlled study included three dietary intervention groups. A total of 95 participants were randomly assigned to the groups, and 75 completed the three-week intervention. Participants were healthy adult volunteers older than 18 years. People with medical conditions that could make participation unsafe or affect the results were excluded.
Study groups and dietary interventions
Participants received an individual meal plan based on their estimated daily energy needs and usual physical activity.
Intermittent fasting with energy restriction: Participants consumed 75% of their estimated daily energy needs within a six-hour eating window. They fasted for the remaining 18 hours.
Continuous energy restriction: Participants consumed 75% of their estimated daily energy needs without a prescribed eating window.
Intermittent fasting without energy restriction: Participants consumed 100% of their estimated daily energy needs within a six-hour eating window. They fasted for the remaining 18 hours.
Participants selected the start of their six-hour eating window according to their daily routine. All groups followed meal plans designed to provide adequate nutrients. The plans emphasized sufficient protein and dietary fiber, along with vegetables, fruit, whole grains, dairy products, and other sources of protein. Participants could drink water, unsweetened tea, and unsweetened coffee. They were instructed to leave at least three hours between their last food intake and bedtime.
Researchers contacted participants by telephone during the intervention to monitor adherence to the meal plans and identify possible adverse events.
Measurements and outcomes
Researchers measured body weight, height, waist circumference, and other body measurements before and after the intervention. They assessed body composition using multifrequency bioelectrical impedance analysis. This method estimates body fat, fat-free mass, skeletal muscle mass, and other body compartments by measuring the body's response to a weak electrical current.
The main outcomes were changes in body weight and body composition after three weeks. Researchers also recorded adverse events, including fatigue, hunger, headaches, difficulties with concentration, and uncomfortable fullness after meals.
Main findings
Participants who followed intermittent fasting with energy restriction lost an average of 2.3 kilograms. Participants who followed continuous energy restriction lost an average of 2.2 kilograms. The difference between these groups was not statistically significant.
Participants who followed intermittent fasting without energy restriction lost an average of 1.1 kilograms. Their weight loss was significantly smaller than that of the other two groups.
The groups did not differ significantly in the amount of body fat lost. The group combining intermittent fasting with energy restriction lost more fat-free mass than the group practicing intermittent fasting without energy restriction. The difference between these groups was statistically significant. However, the study did not find a statistically significant difference in fat-free mass loss between intermittent fasting with energy restriction and continuous energy restriction.
No serious adverse events were reported. Fatigue was more frequent in the group combining intermittent fasting with energy restriction than in the continuous energy restriction group. Uncomfortable fullness or overeating was more frequent in the group practicing intermittent fasting without energy restriction than in the continuous energy restriction group.
Conclusion
The study found that intermittent fasting combined with reduced energy intake did not lead to significantly greater weight loss or body fat loss than continuous energy restriction over three weeks. Limiting eating hours without reducing prescribed energy intake resulted in less weight loss. The findings suggest that both energy intake and diet quality are important when considering changes in body weight and body composition.
The study was limited by its short duration and relatively small number of participants. Body composition was assessed using bioelectrical impedance analysis rather than dual-energy X-ray absorptiometry. Further research is needed to determine the long-term effects of these eating patterns.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Intermittent Fasting with Energy Restriction | Experimental | Behavioral: Intermittent Fasting with Energy RestrictionParticipants followed a six-hour daily eating window and consumed 75% of their estimated daily energy requirements for three weeks. |
| Energy Restriction without Intermittent Fasting | Active comparator | Behavioral: Energy Restriction without Intermittent FastingParticipants consumed 75% of their estimated daily energy requirements for three weeks, without a prescribed six-hour eating window. |
| Intermittent Fasting without Energy Restriction | Experimental | Behavioral: Intermittent Fasting without Energy RestrictionParticipants followed a six-hour daily eating window and consumed 100% of their estimated daily energy requirements for three weeks. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- Adults aged over 18 years. Interest in and willingness to spend time preparing and consuming meals according to the prescribed dietary plan.
Key exclusion criteria (2 listed)
- Pregnancy or breastfeeding. Presence of a pacemaker or insulin pump. Underweight (BMI < 18.5 kg/m²). Cancer, gout, severe gastrointestinal disease, kidney disease, diabetes mellitus, autoimmune disease, thyroid disease, or eating disorders.
- History of organ transplantation. Use of warfarin. Inability to consume the prescribed foods, including adherence to a vegan diet.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Intermittent Fasting with Energy RestrictionParticipants followed a six-hour daily eating window and consumed 75% of their estimated daily energy requirements for three weeks. | Behavioural | Intermittent Fasting with Energy Restriction |
| Energy Restriction without Intermittent FastingParticipants consumed 75% of their estimated daily energy requirements for three weeks, without a prescribed six-hour eating window. | Behavioural | Energy Restriction without Intermittent Fasting |
| Intermittent Fasting without Energy RestrictionParticipants followed a six-hour daily eating window and consumed 100% of their estimated daily energy requirements for three weeks. | Behavioural | Intermittent Fasting without Energy Restriction |
Primary outcome
Change in Body Weight
Time frame: Baseline and after 3 weeks of dietary intervention
Change in body weight (kg) from baseline to the end of the three-week dietary intervention. Body weight was measured before and after the intervention, and the changes were compared between the three intervention groups.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Nov 2026.
- Results publication: PubMed 39512696Cermakova E, Forejt M, Cermak M. The Influence of Intermittent Fasting on Selected Human Anthropometric Parameters. Int J Med Sci. 2024 Oct 7;21(14):2630-2639. doi: 10.7150/ijms.99116. eCollection 2024.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Intermittent Fasting with Energy Restriction, Energy Restriction without Intermittent Fasting and Intermittent Fasting without Energy Restriction in people with Intermittent Fasting, Body Weight, and Body Composition, run by Masaryk University at 1 site in Czechia.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 3 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Czechia. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Body Weight (time frame: Baseline and after 3 weeks of dietary intervention). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07912255, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Nov 2026.