1. Introduction
cardiometabolic disease, weight loss, cardiovascular dysfunction
INSULIN RESISTANCE, CARDIOVASCULAR DISEASE, TYPE 2 DIABETES
Timing of nutrient intake for athletes may affect exercise performance and cardiometabolic factors. Our objective was to examine the effect of time-restricted eating (TRE) on cardiometabolic health. Using a cross-over study design, 15 endurance-trained male runners were randomized to either a normal dietary pattern (ND) first (12 h eating/fasting times) followed by time-restricted eating (TRE) pattern (16 h fast; 8 h eating) or the reverse, with a 4-week washout period between interventions. Body composition, resting energy expenditure, blood pressure and serum insulin, glucose and lipids were measured using standard laboratory methods. Exercise training and dietary intake (calories and macronutrients) were similar across interventions. No significant differences were observed in resting energy expenditure, markers of insulin resistance, serum lipids or blood pressure. Body composition did change significantly (There are various forms of intermittent fasting (IF). This manuscript will focus on time-restricted eating (TRE), a form of IF that is growing in popularity. This regimen involves a decrease in the window of eating each day, essentially extending the overnight fast, which may or may not result in a decrease in caloric intake. This dietary approach can be used by overweight/obese individuals looking to lose body fat and improve their overall health. Likewise, this diet can also be used by normal weight and otherwise healthy persons who want to improve their health independent of weight loss. Studies show that by extending the overnight fast, as done with TRE, one can expect to see a decrease in risk for various metabolic conditions such as cardiovascular disease, type 2 diabetes, and more. One iteration is the “16/8” diet, where individuals fast for 16 h of the day and eat ad libitum for the remaining 8 h [One important consideration unique to endurance-trained athletes is that they are at risk for being in a low energy availability (LEA) state, which can lead to cardiovascular dysfunction as evidenced by disturbances in the blood lipid profile [Peer-reviewed literature is sparse and contains conflicting information about the effects of TRE in athletes. In addition, we know of no study that had used a longitudinal randomized crossover design. Thus, the aim of this study is to examine the effects of four weeks of the 16/8 TRE diet compared to a normal eating window of 12 h fasting and 12 h eating on body composition, resting energy expenditure, and biomarkers of cardiometabolic disease risk using a randomized crossover study design in competitive male endurance runners.