Exercise Duration for Maximum Fat Burning

I often have the question asked - "How much cardio work do I need to do to burn fat?"

The answer is - "As much as you can." (Within safety and injury/overuse boundaries, of course.)

The table below depicts the percentage of fat used as an energy source (compared to carbohydrates) over time.





Note that at 30 minutes of exercise about 60% of your energy is sourced from carbohydrates while fat supplies about 40%. At the 2-hour mark, energy is sourced at a ratio of 50%-50% and as exercise time increases fat is used more and more as the primary source of energy.

So, the longer you can exercise at a moderate intensity, the more fat you are going to burn. Of course extended periods of exercise (greater than 2-hours) is going to be difficult for most people to undertake. However, the important thing to note is that even at 30 minutes you are sourcing about 40% of your energy from fat. So, get moving (for at least 30 minutes) for as long as you can to maximise your fat burning.

Enjoy your exercising!

Steve