Comment by tsimionescu

The article says pretty explicitly that, while you do burn more calories while exercising, your body finds other ways to compensate and generally keeps about the same total energy expenditure in a day.

I'm pretty sure this doesn't apply to extreme cases like modern athletes, who explicitly push their bodies in many ways that normal fit people don't, and who have teams of doctors and coaches that can force them to keep up with exercise and diet even when their bodies are telling them to stop.