Should I do more than one workout a day?

As I started working out and getting involved with others who were doing the same program, I noticed a lot of people mentioned they were "doing doubles", which essentially means two workouts per day. I know off hand it sounds like a great idea and a guaranteed successful results producer, but I wanted to check it out. Essentially, they say to either split up ONE workout or do two workouts per day and give the next day as a rest. So really, it is NOT recommended to work out twice a day. The number one reason being rest and burnout. The other reason being it may actually backfire unless you also tweak your diet and food intake to account for the second workout you are doing. So here is the article I decided summed it up best.

The Benefits of Working Out Twice a Day
When you exercise twice a day, you may actually get more fat burning benefits and faster results. Here's why.
http://www.associatedcontent.comarticle/1008074/the_benefits_of_working_out_twice_a.html