title: The effect of advice to walk 2000 extra steps daily on food intake.
abstract: BACKGROUND
  It is currently unclear how physical activity and diet interact within the ranges of activity seen in the general population. This study aimed to establish whether a small, acute, increase in physical activity would lead to compensatory change in energy intake and nutrient balance, and to provide power analysis data for future research in this field.
  
  
  METHODS
  Twelve participants were studied over 7 days of habitual activity and 2 weeks after instruction to increase physical activity by 2000 steps per day. Physical activity was assessed using a diary, the 'activPAL' activity monitor and a pedometer. Dietary analyses from prospective food diaries were compared between the first and third weeks.
  
  
  RESULTS
  Participants increased step-counts (+2600 steps per day, P = 0.008) and estimated energy expenditure (+300-1000 kJ day(-1), P = 0.002) but did not significantly change their energy intake, dietary composition or number of meals per day. From reverse power analysis 38 participants would be needed to exclude a change in energy intake of 400 kJ day(-1) with 90% power at P < 0.05; 400 kJ day(-1) would compensate for a 2000 steps per day increase in physical activity.
  
  
  CONCLUSIONS
  These results did not demonstrate any compensatory increase in food consumption when physical activity was increased by walking an average of 2600 additional steps per day. Power analysis indicates that a larger study (n = 38) will be necessary to exclude such an effect with confidence.
authors.affiliation: Department of Human Nutrition, Division of Developmental Medicine, University of Glasgow, Glasgow, UK.
authors.forename: A-A
authors.initials: AA
authors.lastname: Koulouri
authors.forename: W W
authors.initials: WW
authors.lastname: Tigbe
authors.forename: M E J
authors.initials: ME
authors.lastname: Lean
mesh_terms: D000328:Adult; D002149:Energy Intake / Q000502:physiology*; D019317:Evidence-Based Medicine; D015444:Exercise / Q000502:physiology*; D005081:Exercise Therapy; D005260:Female; D006293:Health Promotion; D006801:Humans; D008297:Male; D009765:Obesity / Q000517:prevention & control / Q000628:therapy*; D013223:Statistics as Topic; D016138:Walking