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The Impact of Intermittent Fasting on Human Metabolism and Cell Autophagy (InterFast)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT02673515
Recruitment Status : Completed
First Posted : February 4, 2016
Last Update Posted : October 23, 2019
University of Graz
Information provided by (Responsible Party):
Medical University of Graz

Brief Summary:
InterFast is a Cohort study with an embedded randomized controlled pilot trial. Study participants will be healthy subjects and subjects who already practice Alternate Day Fasting. The trial will include 100 participants (50 Participants in Alternate Day Fasting group and 50 participants in the control group). Those participants in the control group will be asked to participate in a short randomized controlled trial, where they will be either allocated to an Alternative Day Fasting group or another control visit.

Condition or disease Intervention/treatment Phase
Excessive Diet Restriction Behavioral: Alternate day fasting Not Applicable

Detailed Description:

Intermittent fasting is a dietary regimen defined by alternating fasting and "feeding" cycles. In addition to caloric restriction (a dietary regimen limited to a daily food intake lower than one's daily caloric needs) only, intermittent fasting seems to activate cell autophagy (cellular "recycling" program) which potentially increases cellular stress resistance and removes accumulated molecules that are potentially toxic. In fact, mice maintained on intermittent fasting without decreased overall food intake show effects on body weight reduction that equal and in some cases even exceed those of calorie restriction. However, additionally, intermittent fasting combined with even a high-fat diet in the feeding periods protects mice from obesity, hyperinsulinemia, hepatic steatosis, and inflammation compared to controls that are fed an ad libitum high-fat diet despite the same calorie intake, making this intermittent fasting regimen a promising approach to reduce morbidity and mortality in various species.

The best described and most widely practiced version of intermittent fasting is the "alternate day diet" or "alternate day fasting" (ADF). In animal models, ADF consists of an ad libitum "feed day" alternated with a 100% restriction "fast day". However in humans, this is often modified to allow a small amount of food consumption on the "fast day" (e.g. 25% of the individual´s energy needs). Findings from recent modified ADF studies showed significant reductions in body weight.

However, knowledge about the molecular effects of the alternate day diet on human metabolism or autophagy is still scarce since detailed analyses of molecular and metabolic parameters remain unexplored, especially in healthy individuals. The overarching aim of this research project is to elucidate in which extent alternate day fasting (and thereby intermittent fasting) influences human physiology in healthy individuals in both short and long term. The secondary objective of this study is to define novel molecular markers of aging and age-related diseases.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 60 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Official Title: The Impact of Intermittent Fasting on Human Metabolism and Cell Autophagy
Study Start Date : April 2015
Actual Primary Completion Date : September 2, 2019
Actual Study Completion Date : September 2, 2019

Arm Intervention/treatment
Active Comparator: Alternate day fasting
Subjects are requested to alternate fast for 4 weeks (alternate an ad libitum "feed day" with a 100% restriction "fast day").
Behavioral: Alternate day fasting
Subjects are requested to fast every other day. Calorie free fluids are allowed.

No Intervention: control group
control group

Primary Outcome Measures :
  1. Insulin sensitivity [ Time Frame: 4 weeks ]
    Difference in the changes of insulin sensitivity

Secondary Outcome Measures :
  1. cell cycle proteins [ Time Frame: 4 weeks ]
    Levels cell cycle proteins (p16, p21, p53)

  2. mammilian target of rapamycin mechanistic Target of Rapamycin (mTOR) [ Time Frame: 4 weeks ]
    Differences in activity of mechanistic Target of Rapamycin (mTOR) between groups

  3. Ras pathway [ Time Frame: 4 weeks ]
    Differences in Ras expression between groups

  4. Apoptosis [ Time Frame: 4 weeks ]
    Differences in cell apoptosis between groups

  5. Mitochondrial damaged [ Time Frame: 4 weeks ]
    Differences in mitochondrial damage between groups

  6. Telomer length [ Time Frame: 4 weeks ]
    Differences in telomere length between groups

  7. Double strand breaks [ Time Frame: 4 weeks ]
    Differences in the amount of double strand breaks between groups

  8. Blood pressure [ Time Frame: 4 weeks ]
    Difference in the change of blood pressure between groups.

Information from the National Library of Medicine

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Ages Eligible for Study:   35 Years to 65 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Body mass index in the range of 22.0 - 27.0 kg/m2,
  • Fasting blood glucose <110mg/dL (without medication)
  • LDL-cholesterol <180 mg/dL (without medication)
  • Blood pressure <140/90 mmHg (without medication)
  • Stable weight (change <± 10%) for 3 months immediately prior to the study,
  • No history of metabolic disorders or cardiovascular disease
  • No acute or chronic inflammatory disorder
  • No current medications to regulate blood sugar, blood pressure or lipids or hormones
  • No heavy drinking (more than 15 drinks/week)
  • No use of tobacco or recreational drugs within past 5 years
  • No dietary restrictions (e.g. vegetarianism and vegan)

Exclusion Criteria:

  • Known Malignancy
  • Women who are pregnant, breast-feeding or trying to become pregnant
  • History of any chronic disease process that could interfere with interpretation of study results
  • Women or men on hormonal supplementation or anti-conceptive hormonal medication for at least 2 months
  • Therapy with antidepressants within past 6 months
  • Regular therapy with acetylsalicylic acid

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT02673515

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Dept. of Internal Medicine, Medical University of Graz
Graz, Austria, 8036
Sponsors and Collaborators
Medical University of Graz
University of Graz
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Principal Investigator: Harald Sourij, MD Medical University of Graz, Auenbruggerplatz 15
Study Chair: Frank Madeo, PhD Karl Franzens University Graz, Austria
Study Chair: Thomas R Pieber, MD Medical University Graz, Austria