Is it Okay to do Cardio Before Breakfast?

First of all lets reveal the theory. It goes like this. An overnight fast lowers blood sugar so glycogen levels fall. This will result in your body using fat as it's primary source of fuel as oppose to glucose. Furthermore the low insulin level from the abundance of food will result in fat brake down and will therefore improved the availability of fatty acids to be used as energy for our morning jog. Believing in this hypothesis of improving your body composition is just silly!

The most important thing to consider whilst lowering your body fat percentage is energy in by comparison to energy out. The harder you exercise the more calories you'll burn afterwards based on the increased metabolism.
Fasting followed by cardiovascular work has been proven to increase the utilisation of fat during the session but this can change based on a number of different physiological aspects. Even if you did predominately burn fat during the workout your body will tap into your glycogen stores to recuperate afterwards anyway but If you tapped into your glycogen stores first you will burn more fat after the workout. This is a much more comfortable way of lowering your body fat as you will have the option to ingest a light meal before training.

Basically any benefit you've made to run before breakfast will be counteracted. Now for more negatives. Your glycogen stores deplete overnight so your body relies on the brake down of amino acids in your muscles. This continues until breakfast but is escalated by morning cardio due to the high energy demand. In a nut she'll you lose muscle tone!

If you want to lower your body fat you simply need to eat less and work your body harder. There is not easy way to go about it.

More on body composition:

Greasing the Pan

http://icankeepup.blogspot.co.uk/2015/09/greasing-pan.html

Salad Dressings for Wicked Body Composition

http://icankeepup.blogspot.co.uk/2015/09/salad-dressings-for-wicked-body.html