Context: In addition to the low energy expenditure induced by sedentary behaviors such as sitting, it has been shown that intense cognitive work can lead to an increase in food intake. Walking Desk provide the opportunity for office workers to replace prolonged sitting at work with light intensity physical activity. Objective: To compare the effects of sitting vs standing vs walking during a cognitive task on energy intake, appetite sensations, food reward and overall energy balance. Methods: Fifteen normal weight (BMI: 24.1 +/- 1.2 kg m(-2)) young men (23.4 +/- 2.1 years) randomly performed three conditions: sitting desk (SitD), standing desk (StD) and walking desk (WD), while performing a 45-min cognitive task. Energy expenditure was measured by indirect calorimetry, regular appetite sensations were assessed using visual analogue scales, energy intake measured during an ad libitum meal and the relative energy intake calculated. Pre and post-test meal food reward was evaluated through the Leeds Food Preference Questionnaire. Results: Relative energy intake decreased by 150 kcal in WD compared with SitD, however it did not reach statistical significance. There were no differences in appetite sensations nor food reward between the three conditions. Energy expenditure was significantly higher in WD (141.8 +/- 13 kcal) than in SitD (78.7 +/- 5 8 kcal) and StD (85.9 +/- 8 kcal) (p <= 0.05). Conclusion: Walking desk use can decrease sedentary time while working without any appetitive compensation. The small reduction in energy balance with walking while working could induce significant health benefits if repeated over time. Future longer studies need to clarify whether active desks can contribute to the prevention or management of weight gain.