From the research I have done, I can't find any scientific evidence that backs up fasted cardio. If you speak to people who swear by fasted cardio, then they will tell you that it works. Before I continue, 'fasted cardio' simply means exercising without eating beforehand (i.e. first thing in the morning).
Fasted cardio can mean one thing - slightly less calories consumed. Think about it - if you wake up and have breakfast straight away as your first meal, and then eat throughout the day too, that will be more calories consumed per day than if you don't eat first thing, but instead workout. That is most likely how you can lose a little more fat by using 'fasted cardio'.
It is a personal thing though.
I myself workout in the mornings, with a protein pre workout shake consumed 30 minutes prior. The mornings are simply when it's convenient for me. I'll admit, sometimes during late afternoons/evenings, I feel 'pumped up' for a workout more than in the mornings, but as mentioned, the mornings are more convenient. I don't personally feel that I have a better fat burning workout in the mornings on a relatively empty stomach (and sometimes I have nothing at all prior to the workout).
I know of some people who have tried fasted cardio, and they have felt weak, lethargic, and their training intensity has decreased. But there will be people who train harder in a fasted state.
The fact that there is no evidence to show that you burn more calories in a fasted state, doesn't mean you shouldn't do it. Give it a try, see how you feel. Working out is a very personal thing, everyone has their own ways/styles, and if a fasted workout suits you better, then go for it. Whatever makes you train harder you should do.
Lee Gregory Fitness
