Fasted Evening Exercise: Performance and Compensatory Eating
Condition: Obesity
Study type: Interventional

Summary: 
      This study will compare the appetite, energy intake, and exercise performance responses to a
      bout of exercise completed in the evening after an extended period of fasting with a similar
      bout of exercise completed in the evening and the morning, after consuming a
      carbohydrate-containing meal.
    

Detailed description: 
      Regular exercise is known to be a successful strategy for improving several facets of health
      and maintaining body weight. However, many people are not engaging in enough exercise, and
      some may not be achieving maximum benefits from the exercise that they already do. Performing
      exercise in the overnight fasted state has been shown to reduce energy intake over the course
      of a single day, without any compensatory reductions in free-living energy expenditure.
      Despite these promising findings, it is likely that not every member of the population is
      logistically able to perform exercise in the morning due to various work, family and social
      commitments, and exercise in the evening may be a logical alternative for these individuals.
      Whether the beneficial effects of overnight fasted exercise can be observed at an alternative
      time of the day (i.e. the evening) is unknown.

      Therefore, the investigators are interested in examining the compensatory appetite and energy
      intake responses following a bout of evening exercise performed after an extended (7 hour)
      period of fasting. Exercise performance will also be assessed as a marker of voluntary energy
      expenditure, which if reduced, has the potential to compensate for the reduced energy balance
      induced by fasted exercise.
    

Intervention name(s): Fasted Evening Exercise; Fed Evening Exercise; Fed Morning Exercise
Intervention type(s): Behavioral; Behavioral; Behavioral
Intervention description(s): A 45 minute exercise session will take place on a stationary cycle ergometer at 18:30, after a 7-hour period of fasting. This will consist of 30 minutes of steady state cycling at 60% of VO2max, followed by an exercise test during which participants will complete as much work as they can within 15 minutes.; A 45 minute exercise session will take place on a stationary cycle ergometer at 18:30, after having consumed a carbohydrate-containing meal (20% estimated energy requirements) 2 hours prior. This will consist of 30 minutes of steady state cycling at 60% of VO2max, followed by an exercise test during which participants will complete as much work as they can within 15 minutes.; A 45 minute exercise session will take place on a stationary cycle ergometer at 10:30, after having consumed a carbohydrate-containing meal (20% estimated energy requirements) 2 hours prior. This will consist of 30 minutes of steady state cycling at 60% of VO2max, followed by an exercise test during which participants will complete as much work as they can within 15 minutes.
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: The study design is a randomised, controlled, crossover design in which participants undertake three exercise conditions in a randomised order with at least a seven day period in between trials.
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Fasted exercise; Energy intake; Energy balance; Appetite; Exercise performance