Not true. Within an average day (pending weight and mass overall as well as heart rate) someone walking 15k+ steps a day could easily come close to matching their daily resting rate. An hour of exercise, yes trivial. But simply just not being sedentary will easily get you to needing 3500-4000 calories just to maintain. Of course that's only 1000-1500 more than a man needs on average, and with how easily replaced it is by bad food choices, yes it could also seem trivial. But if maintaining consistency, it could be the difference between success and failure.

http://www.nutritionmd.org/nutrition_tips/nutrition_tips_understand_foods/carbs_versus.html

http://www.healthline.com/health/food-nutrition/simple-carbohydrates-complex-carbohydrates#3

http://www.newhealthadvisor.com/What-Do-Complex-Carbohydrates-Break-Down-Into.html

Bottom line, be slightly active and you're fine. Be sedentary and suffer the consequences of your own actions.