Intermittent Fasting, Obesity, Overweight and Obesity, Time Restricted Eating, Time Restricted Feeding
Conditions
Brief summary
Time-restricted eating (TRE) is a dietary approach that aims to increase fasting time and decrease the eating window. Promising TRE effects on weight loss and improvements in some cardiometabolic risk factors have been reported in studies in animals and humans. However, the impacts of TRE combined with aerobic exercise training in individuals with overweight and obesity have been insufficiently investigated. Additionally, aerobic training performed in a fasted state appears to promote physiological adaptations that may improve the metabolic health in individuals with overweight and obesity. The present study investigates the effects of 8 weeks of TRE associated with aerobic training in a fasted state versus a fed state on body composition and cardiometabolic parameters in women with overweight and grade 1 obesity.
Interventions
BEHAVIORALDietary and Exercise Approaches
Intermittent fasting plus energy restriction combined with aerobic exercise performed in a fasted state.
BEHAVIORALDietary Approach
Intermittent fasting plus energy restriction without aerobic exercise training.
Sponsors
Federal University of Rio Grande do Sul
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Outcomes Assessor)
Eligibility
Sex/Gender
FEMALE
Age
20 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
* Female; * Body mass index (BMI) between 25 and 34.9 kg/m²; * Age between 20 and 40 years; * Not engaged in any structured exercise program; * Weight stable for \ 3 months before the beginning of the study; * Able to give written informed consent.
Exclusion criteria
* Current smoker; * Habitual drinkers (\>1 serving/day) of alcoholic beverages; * Cardiometabolic diseases (dyslipidemia, diabetes, hypertension, etc); * Current treatment with medication or supplements which significantly affect the main studied variables; * Bariatric surgery; * Night-shift workers; * Strict vegetarian/vegan; * Pregnancy, planned pregnancy (within the study period), lactating; * Postmenopausal women; * Self-reported menstrual cycle irregularities; * Habitual fasting window \>16 hours; * Concomitant participation in other studies.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Insulin sensitivity (indices) | Change from baseline. Measured at baseline and after 8 weeks. | Including but not limited to the Sensitivity Matsuda index |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Fasting insulin levels (µIU/mL) | Change from baseline. Measured at baseline and after 8 weeks. | Measured by enzyme-Linked Immunosorbent Assay |
| Fasting glucose levels (mg/dL) | Change from baseline. Measured at baseline and after 8 weeks. | Measured by colorimetric method |
| Glucose tolerance | Change from baseline. Measured at baseline and after 8 weeks. | Measured by oral glucose tolerance test (2-h OGTT) |
| Fasting lipid profile levels | Change from baseline. Measured at baseline and after 8 weeks. | Measured by colorimetric method |
| β cell function (indices) | Change from baseline. Measured at baseline and after 8 weeks. | Including but not limited to HOMA-β |
| Fat Mass (kg) | Change from baseline. Measured at baseline and after 8 weeks. | Measured by Dual-energy X-ray Absorptiometry under fasting condition. |
| Fat Percentage (%) | Change from baseline. Measured at baseline and after 8 weeks. | Measured by Dual-energy X-ray Absorptiometry under fasting condition. |
| Fat Free Mass (kg) | Change from baseline. Measured at baseline and after 8 weeks. | Measured by Dual-energy X-ray Absorptiometry under fasting condition. |
| Body Weight (kg) | Change from baseline. Measured at baseline and after 8 weeks. | Measured by Dual-energy X-ray Absorptiometry under fasting condition. |
| Bone Mineral Content (kg) | Change from baseline. Measured at baseline and after 8 weeks. | Measured by Dual-energy X-ray Absorptiometry under fasting condition. |
| Insulin resistance (indices) | Change from baseline. Measured at baseline and after 8 weeks. | Including but not limited to Homeostatic Model Assessment for Insulin Resistance (HOMA-IR). |
| Fasting ketones (β-hydroxybutyrate) levels (mmol/L) | Change from baseline. Measured at baseline and after 8 weeks. | — |
| Resting metabolic rate (Kcal/day) | Change from baseline. Measured at baseline and after 8 weeks. | Measured by indirect calorimetry under resting and fasting conditions. |
| Substrate Oxidation (respiratory exchange ratio) | Change from baseline. Measured at baseline and after 8 weeks. | Measured by indirect calorimetry under resting and fasting conditions. |
| Absolute Peak oxygen consumption | Change from baseline. Measured at baseline and after 4, and 8 weeks. | Measured by an open-circuit spirometry system. Absolute value expressed in litres of oxygen per minute (L/min). |
| Relative Peak oxygen consumption | Change from baseline. Measured at baseline and after 4, and 8 weeks. | Measured by an open-circuit spirometry system. Relative to body weight and expressed in milliliters of oxygen per minute (mL/kg/min). |
| Fasting Leptin Levels | Change from baseline. Measured at baseline and after 8 weeks. | Measured by enzyme-Linked Immunosorbent Assay |
| Fasting Adiponectin Levels | Change from baseline. Measured at baseline and after 8 weeks. | Measured by enzyme-Linked Immunosorbent Assay |
| Inflammatory Markers Levels | Change from baseline. Measured at baseline and after 8 weeks. | Including but not limited to TNF-α (tumor necrosis factor-alpha) and IL-10 (Interleukin-10); Measured by enzyme-Linked Immunosorbent Assay |
| LDL-cholesterol levels | Change from baseline. Measured at baseline and after 8 weeks. | Measured using the Friedewald equation. |
| Non-HDL-cholesterol levels | Change from baseline. Measured at baseline and after 8 weeks. | Calculated as total cholesterol minus HDL-cholesterol. |
| Body Mass Index (kg/m^2) | Change from baseline. Measured at baseline and after 8 weeks. | Calculated from weight in kilograms divided by height in meters squared. |
Outcome results
None listed