Energy Intake, Nonexercise Physical Activity, and Weight Loss in Responders and Nonresponders: The Midwest Exercise Trial 2

Objective: To compare energy intake, total daily energy expenditure (TDEE), nonexercise energy expenditure (NEEx), resting metabolic rate (RMR), nonexercise physical activity (NEPA), and sedentary time between participants with weight loss <5% (nonresponders) vs. ≥5% (responders) in response to exercise.

Methods: Adults (18-30 years) with overweight/obesity (BMI 25-40 kg/m(2) ) were randomized to exercise: 5 days/week, 400 or 600 kcal/session, 10 months.

Results: Of the participants, 40 responded and 34 did not respond to the exercise protocol. Nonresponder energy intake was higher vs. responders, significant only in men (P=0.034). TDEE increased only in responders (P=0.001). NEEx increased in responders and decreased in nonresponders, significant only in men (P=0.045). There were no within- or between-group differences for change in RMR. NEPA increased in responders and decreased in nonresponders (group-by-time interactions: total sample, P=0.049; men, P=0.016). Sedentary time decreased in both groups, significant only in men.

Conclusions: Men who did not lose weight in response to exercise (<5%) had higher energy intake and lower NEEx when compared with men losing ≥5%. No significant differences in any parameters assessed were observed between women who lost <5% vs. those losing ≥5%. Factors associated with the weight loss response to exercise in women warrant additional investigation.