title: Effect of a thermogenic beverage on 24-hour energy metabolism in humans.
abstract: OBJECTIVE
  To test whether consumption of a beverage containing active ingredients will increase 24-hour energy metabolism in healthy, young, lean individuals.
  
  
  METHODS
  Thirty-one male and female subjects consumed 3 x 250-mL servings of a beverage containing green tea catechins, caffeine, and calcium for 3 days in a single-center, double-blind, placebo-controlled, cross-over design study. On the 3rd day, 23-hour energy metabolism, extrapolated to 24-hour, was measured in a calorimeter chamber. Blood pressure and heart rate were measured, and total day and night urines were analyzed for urea and catecholamine excretion.
  
  
  RESULTS
  Twenty-four-hour energy expenditure (EE) and 24-hour fat oxidation were lower in women than in men (p < 0.0001 and p < 0.015, respectively). Although there were no treatment or treatment/gender effects on substrate oxidation, treatment increased 24-hour EE by 106 +/- 31 kcal/24 hours (p = 0.002), equivalent to 4.7 +/- 1.6 kcal/h (day; p = 0.005) and 3.3 +/- 1.5 kcal/h (night; p = 0.04). No significant differences were observed in hemodynamic parameters.
  
  
  CONCLUSIONS
  The present study provides evidence that consumption of a beverage containing green tea catechins, caffeine, and calcium increases 24-hour EE by 4.6%, but the contribution of the individual ingredients cannot be distinguished. Although this increase is modest, the results are discussed in relation to proposed public health goals, indicating that such modifications are sufficient to prevent weight gain. When consumed regularly as part of a healthy diet and exercise regime, such a beverage may provide benefits for weight control.
authors.affiliation: Department of Physiology, Lausanne University, Lausanne, Switzerland.
authors.forename: Servane
authors.initials: S
authors.lastname: Rudelle
authors.forename: Mario G
authors.initials: MG
authors.lastname: Ferruzzi
authors.forename: Isabelle
authors.initials: I
authors.lastname: Cristiani
authors.forename: Julie
authors.initials: J
authors.lastname: Moulin
authors.forename: Katherine
authors.initials: K
authors.lastname: Macé
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Acheson
authors.forename: Luc
authors.initials: L
authors.lastname: Tappy
mesh_terms: D000293:Adolescent; D000328:Adult; D001628:Beverages; D002395:Catecholamines / Q000652:urine; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004734:Energy Metabolism / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D018670:Monitoring, Ambulatory; D010919:Placebos; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000378:metabolism; D022722:Thermogenesis / Q000187:drug effects*
chemical_list: D002395:Catecholamines; D010919:Placebos