Time Restricted Feeding in Male Runners
Condition: Fasting; Intermittent Fasting; Athletic Performance; Cardiovascular Risk Factor; Resting Energy Expenditure
Study type: Interventional

Summary: 
      This is a cross-over intervention study designed to evaluate how four weeks of time
      restricted feeding (16 hours fasting and 8 hours feeding), compared to four weeks of a more
      traditional eating pattern (12 hours fasting and 12 hours feeding), affects resting energy
      expenditure, subjective and biochemical markers of satiety and hunger, body composition,
      cardiovascular health, substrate utilization and fitness in male competitive runners.
    

Detailed description: 
      Weight loss and improvements in body composition (increasing muscle mass and decreasing fat
      mass) are common goals for both dieters and athletes. Although a traditional method of
      achieving this has been accomplished through caloric restriction, an alternate method that is
      becoming increasingly popular is fasting. Fasting is described as the absence of food and/or
      calorie-containing beverage consumption for a period of time. The majority of people fast for
      8-10 hours daily, which occurs during the overnight period when people are asleep
      Intermittent fasting, specifically time-restricted feeding (TRF), has recently gained
      popularity because it is a more sustainable means of practicing fasting and it has been shown
      to enhance the loss of fat mass with or without caloric restriction. It has also been shown
      to enhance overall health due to reports of reduced fasting glucose, insulin resistance,
      triglycerides, and reduced total and low-density lipoprotein (LDL) cholesterol levels in
      obese women. Despite its growing popularity among athletes, there is scarce research on how
      adhering to this type of diet pattern affects athletic performance and other biochemical
      markers related to health. The participants in this study will be randomly assigned to either
      a traditional (12/12) or a time restrictive (16/8) eating pattern in a crossover design. Each
      pattern will last for four weeks with a minimum two week washout in between, and the
      participants will consume the same calorie and macronutrient amounts based on recommendations
      made by the American College of Sports Medicine (ACSM) for both eating patterns. The 12/12
      pattern will require subjects to consume 5 meals (breakfast, lunch, dinner, and two snacks)
      per day within a 12 hour period suggested to be around 8am, 10am, 12pm, 3pm, and 7pm. The
      16/8 pattern will require subjects to consume 3 meals in an 8-hour period suggested to be
      around 12pm, 3pm, and 7pm. Subjects may only consume water, unsweetened coffee, or
      unsweetened tea (no artificial sweeteners) during their periods of fasting. Subjects will
      perform all exercise in the morning before 8 am in the fasted state. Subjects will visit the
      Western Human Nutrition Research Center (WHNRC) for test days at baseline (study day 1),
      after four weeks of the first dietary intervention (study day 28), and at the start (study
      day 43) and end of the second dietary intervention (study day 70), for a total of 4 test days
      over the duration of 10 weeks.
    

Intervention name(s): Time Restrictive Feeding; Traditional Eating Pattern
Intervention type(s): Behavioral; Behavioral
Intervention description(s): Volunteers will adhere to a form of time restrictive feeding, 16 hours fasting and 8 hours eating per day.; Volunteers will adhere to a more traditional eating pattern, 12 hours fasted and 12 hours eating per day.
Other intervention name(s): Intermittent Fasting; Normal Diet
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Basic Science