It depends what the posts are saying, but a very active person can burn around 5,000 calories in a day or more from working out. An example of a sport that burns tons of calories is training that people do in Muay Thai Kickboxing.
Aerobic activity burns fat and carbs, while anaerobic activity burns only carbs, so not all calories you burn are burning the same kind of fuel. This is because the body has 3 energy systems.
Fitness theory
If you want to burn calories first you need to reduce the amount of cal. consumed the next is to exercise by doing strength training and cardio!
Learn to do kettlebell swing and Interval training.