I want to start off by saying that this is my opinion, and I know other people will have their own opinions and will disagree with me.
I'm always researching, learning, reading, and follow top nutritionists and personal trainers, and with all that, and my personal experience, I have my own opinion on the best way to burn fat.
Pump that iron!
Back in the day, fat burning used to be running on a treadmill or riding a stationary bike. These days, if your personal trainer still does that, sack him/her. The way the top trainers do things nowadays is to use weights. Think about it, lifting something remotely heavy requires energy, so using more energy to lift weights will burn more calories. Have you ever helped someone move house? lifting a lot of things? if you have, you'll soon know that you can easily sweat, get out of breathe and feel tired after lifting heavy objects, it's the same with weight lifting.
Now, you don't need to train like a bodybuilder, you just need to lift weights that cause a tough enough resistance. If you look at a lot of body weight exercises - squats, lunges, press ups, pull ups and so on, they are all good, but by adding weights to them, you will be working harder, therefore burning more calories. As well as those exercises, you have ones such as a deadlift, clean and press, upright barbell row and so on. All exercise which burn calories, and by adding them into a circuit, you will be working hard!
Burning fat is all about pushing your body, and by adding weights you will be pushing your body harder because lifting weights requires more effort. Compare that approach to running on a treadmill. Treadmill running does burn calories, but not as much as weight training. Also, treadmill running is rather boring and people soon become fed up with it, whereas weight training is far more engaging and fun.
I know a guy who used to be fairly overweight and he decided to train like a bodybuilder - just heavy weight training. Me and a few others did tell him that he might want to just concentrate on fat burning first, rather than just worrying how much he could lift. He went ahead with it regardless. After a while there were two differences I noticed - 1) His strength did improve, and 2) he lost body fat. It wasn't that me and the others didn't think training that way would burn fat, we knew it would, but jumping straight into heavy lifting isn't the ideal thing to do, and only worrying about how much he can lift, not exactly the best strategy. But end of the day, the training he did, worked. He shed body fat, and his strength increased, so he just stuck to it, and now he is in pretty good shape.
So, before you think you should go straight to the cardio machines to burn body fat, give the weights a try. I advise you train with someone experienced with weights, or hire a personal trainer, otherwise you could pick up an injury.
Lee Gregory Fitness