Sounds like an excuse for being too lazy to work out. Cardio effectively burns fat because growth hormone is being secreted. Growth hormone's effect on the body is similar to steroids: burns fat while making new muscle.

The problem is true cardio means getting the heart rate above 80% of maximum. A study at Laval University showed much greater fat loss from cyclists working above 90% of max for 10 minutes a day, compared with cyclists working at 60% of max for an hour a day.