title: Nonprescribed physical activity energy expenditure is maintained with structured exercise and implicates a compensatory increase in energy intake.
abstract: 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.
  
  
  METHODS
  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 ≈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 ≈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.
authors.affiliation: Sport, Health and Exercise Science, School for Health, University of Bath, Bath, United Kingdom.
authors.forename: James E
authors.initials: JE
authors.lastname: Turner
authors.forename: Daniella
authors.initials: D
authors.lastname: Markovitch
authors.forename: James A
authors.initials: JA
authors.lastname: Betts
authors.forename: Dylan
authors.initials: D
authors.lastname: Thompson
mesh_terms: D015992:Body Mass Index; D002149:Energy Intake; D004734:Energy Metabolism; D015444:Exercise / Q000502:physiology*; D005081:Exercise Therapy; D006801:Humans; D020738:Leptin / Q000097:blood; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D050177:Overweight / Q000378:metabolism / Q000628:therapy*; D057185:Sedentary Behavior; D015431:Weight Loss
chemical_list: D020738:Leptin