Nonprescribed physical activity energy expenditure is maintained with structured exercise and implicates a compensatory increase in energy intake

• Published in: The American journal of clinical nutrition Vol. 92; no. 5; pp. 1009 - 1016
• Main Authors: Turner, James E, Markovitch, Daniella, Betts, James A, Thompson, Dylan
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Clinical Nutrition 01.11.2010; American Society for Nutrition; American Society for Clinical Nutrition, Inc
• Subjects: Biological and medical sciences; Body Mass Index; body weight; energy expenditure; Energy Intake; Energy Metabolism; Exercise; Exercise - physiology; Exercise Therapy; Feeding. Feeding behavior; Fundamental and applied biological sciences. Psychology; human nutrition; Humans; leptin; Leptin - blood; Male; Men; Middle age; Middle Aged; middle-aged adults; Motor Activity - physiology; Nutrition; Obesity; overweight; Overweight - metabolism; Overweight - therapy; physical activity; Proteins; Sedentary Behavior; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Weight Loss; Physical exercise; Human; Energy; Energetic cost
• ISSN: 0002-9165; 1938-3207
• DOI: 10.3945/ajcn.2010.29471

BACKGROUND: Exercise interventions elicit only modest weight loss, which might reflect a compensatory reduction in nonprescribed physical activity energy expenditure (PAEE). OBJECTIVE: The objective was to investigate whether there is a reduction in nonprescribed PAEE as a result of participation in a 6-mo structured exercise intervention in middle-aged men. DESIGN: Sedentary male participants [age: 54 ± 5 y; body mass index (in kg/m²): 28 ± 3] were randomly assigned to a 6-mo progressive exercise (EX) or control (CON) group. Energy expenditure during structured exercise (prescribed PAEE) and nonprescribed PAEE were determined with the use of synchronized accelerometry and heart rate before the intervention, during the intervention (2, 9, and 18 wk), and within a 2-wk period of detraining after the intervention. RESULTS: Structured prescribed exercise increased total PAEE and had no detrimental effect on nonprescribed PAEE. Indeed, there was a trend for greater nonprescribed PAEE in the EX group (P = 0.09). Weight loss in the EX group (-1.8 ± 2.2 kg compared with +0.2 ± 2.2 kg in the CON group, P < 0.02) reflected only [almost equal to]40% of the 300-373 kcal/kg body mass potential energy deficit from prescribed exercise. Serum leptin concentration decreased by 24% in the EX group (compared with 3% in the CON group, P < 0.03), and we estimate that this was accompanied by a compensatory increase in energy intake of [almost equal to]100 kcal/d. CONCLUSIONS: The adoption of regular structured exercise in previously sedentary, middle-aged, and overweight men does not result in a negative compensatory reduction in nonprescribed physical activity. The less-than-predicted weight loss is likely to reflect a compensatory increase in energy intake in response to a perceived state of relative energy insufficiency.