Fat-burning zone
In the fat-burning zone, the body gets the largest share of its energy from fat – but for weight loss, total energy is what counts, not the share.
Ausführlich erklärt
The “fat-burning zone” is the intensity range in which your body gets the largest share of its energy from fat – at light to moderate effort, roughly 60 to 75% of your maximum heart rate. Studies (Achten and Jeukendrup, 2003) found the highest rate of fat burning at around 60 to 65% of maximal oxygen uptake (the standard measure of endurance capacity).
The catch lies in the word “share”. When you walk at an easy pace, perhaps half of your energy comes from fat; when you run fast, only a third – but running uses much more energy overall. Here's an example: 30 minutes of walking = about 150 kilocalories, 75 of them from fat. 30 minutes of jogging = about 300 kilocalories, 100 of them from fat. So the more intense session actually burns more fat in absolute terms, even though the share is smaller.
And even more importantly: whether you lose fat over the weeks is decided by your overall balance of energy intake and expenditure – not by which fuel happened to be in the furnace during a single training session. If you burn mainly carbohydrates during exercise, your body draws all the more on fat afterwards while you're at rest. Over 24 hours, it evens out.
Why the zone still makes sense: you can keep up easy training for a long time and often, it puts little strain on your body and it teaches your metabolism to use fat more efficiently – a real benefit for endurance and health. That's why it's exactly the right range for beginners and people who are significantly overweight.
The practical takeaway: choose your intensity based on what you can manage regularly and what you enjoy. Lots of easy movement plus some strength work and the occasional faster session – that's how you create the deficit that really counts.