It's what you eat

I strongly advocate exercise and physical activity for the benefit it provides.  Exercise reduces the incidence of disease, leads to a longer, active life and improves mood.  Even though I do not promote exercise as a means of weight loss, people often ask me what form of exercise (e.g., running vs swimming) is better for burning calories and whether intensity or duration is better.  People are also interested in what type of exercise will burn fat. 
I don't have an answer.  Exercise is an important part of a healthy lifestyle.  If a person is really interested in their weight and excess calories - then I suggest they consider what they are eating.

A month or so ago, my stance was vindicated in an article about exercise.  A kinesiology professor from McMasters University was asked about High Intensity Interval Training, or HIT.  Someone asked the exercise specialist if HIT was better for losing weight than other forms of exercise and Dr. Gibala replied, 

The main way to lose weight is by what we put in our mouth, not by exercising to burn calories.