None listed
Conditions
Brief summary
This project will carry out a controlled randomised crossover trial, enrolling up to 20 healthy volunteers from ages 18-70 years over the next 3 years. The intervention involves a 3-day water-only fasting, with or without a single bout of glycogen depleting exercise on cycle ergometer. We and others have shown that prolonged fasting, turns on autophagy and proteostatic pathways via up-regulation of several “longevity genes”. However, we do not yet understand the timing and the dose-response of these beneficial cell and metabolic signalling adaptations in humans. The proposed study will determine the effects of a 3-day fast on activation of autophagy and associated stress-resistance pathways, and test the hypothesis that a single bout of exercise enhances this effect. This study is part of an ongoing research effort at the University of Sydney multidisciplinary hub ‘Charles Perkins Centre’ and Sydney Local Health District on healthy ageing and prevention of cardiometabolic diseases.
Interventions
Arm 1: 3-day water-only fasting (comparator)
Arm 2: 3-day water-only fasting with one bout of glycogen-lowering cycling exercise at the beginning of the fast (intervention).
After completion of the intervention/comparator, and following the 4-week washout period, the two arms will be crossed over, and the intervention/comparator will be repeated. After 4 week wash out period, and before the second period of fasting, "Month 1" timepoint samples and data will be collected (baseline #2). Finally,
Arm 1: 3-day water-only fasting (comparator) Arm 2: 3-day water-only fasting with one bout of glycogen-lowering cycling exercise at the beginning of the fast (intervention). After completion of the intervention/comparator, and following the 4-week washout period, the two arms will be crossed over, and the intervention/comparator will be repeated. After 4 week wash out period, and before the second period of fasting, "Month 1" timepoint samples and data will be collected (baseline #2). Finally, 4 weeks after completion of the second bout of fasting, "Month 2" follow up timepoint samples and data will be collected. Adherence to the fasting intervention will be monitored via the weighted food diary and blood glucose and ketone monitoring. After each fasting period, participants will revert to their usual diets gradually, over the refeeding period of 4 days. The participants will be advised to start with low carbohydrate vegetable soup as their first meal and to consume a low carbohydrate vegetarian diet consisting of vegetables, salads, soups, and fruit for the first day. Participants will be advised to start with small portions and increase portion size gradually, returning to unrestricted/usual diets during the 4 day refeeding period. The diet will not be imposed or controlled, however, it will be documented via 4-day weighted food diary. Fasting will be carried out at home with daily clinic visit each morning. Adherence will be tracked by daily questionnaires, blood glucose and ketone measurements. The glycogen-lowering cycling exercise will be performed at the clinic on the first day of fasting. Participants will cycle at 70 rpm, constant power output, at an intensity corresponding to 70% of their previously determined peak power output for 60 min on a cycle ergometer. After 5 minutes rest period, participants will perform 6 repeated 1-min sprints at 90 rpm and 125% peak power output, separated by 1-min rest periods.
Sponsors
University of Sydney
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Educational / counselling / training
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to 70 Years
Healthy volunteers
Yes
Inclusion criteria
1. Disease status/ or disease group for study: healthy, without disability that may impede cycling exercise. 2. Sex: male and female 3. Age range: 18-70 years old 4. BMI range: 20-40kg/m2 5. Basic written and spoken English language proficiency needed for the completion of the questionnaires. 6. Willing and able to undergo all study evaluations and adhere to exercise and fasting interventions.
Exclusion criteria
1. Participants that are pregnant, breastfeeding or of childbearing potential who are not willing to avoid becoming pregnant during the study. 2. History of chronic disease processes that according to the investigators could interfere with ability to undergo exercise tests fasting or may affect the interpretation of results. 3. People with comorbidities such as (but not limited to) hypertension, diabetes, diagnosed cardiovascular disease 4. History of supplement and medication use that may affect the interpretation of results. 5. Health condition dietary requirements or life situation that would interfere with study participation and compliance. 6. Unintentional weight loss (>10% body weight) over the past 5 years, smoking, psychiatric or behavioural problems (history of drug and alcohol abuse, eating disorder). 7. Inability to perform cycling exercise: incremental peak power test during the baseline assessment visit, or the 90-minute glycogen-depleting exercise at the start of the fasting intervention. 8. People judged at the investigator’s discretion as being unsuitable to participate.
Outcome results
None listed