You increase the number of jogging sessions to lose weight, but your figure doesn’t really change. However, a team of researchers has highlighted a much gentler activity, which has gone viral on gym mats, which shakes up everything we thought we knew about cardio.
Published in 2025 in the journal , their study looked at the “12-5-30” hill walking session and compared it directly to running. Same number of calories burned, different intensities, but a clear winner when it comes to fat burning…and it’s not racing.
Incline walking 12-5-30: the gentle activity that changes everything
The protocol is simple: the 12-5-30 method consists of walking for 30 minutes on a treadmill inclined at 12%, at a speed of 5 km/h. Fitgirls have made it their ritual to gently sculpt the lower body, with much less shock than classic running on asphalt or flat treadmill.
Intrigued by this craze, the researchers compared this inclined walk to a running session by setting a key parameter: each participant had to burn exactly the same number of calories, whatever the activity chosen. The results show that, even with equal caloric expenditure, the two exercises do not use at all the same internal “fuels”.
Why walking on an incline burns more fat than running
In the study, treadmill walking took longer, since it was less intense, but fat oxidation was much greater. Concretely, the body drew more on lipids as a source of energy, while the race mainly exploited carbohydrates stored in the form of glycogen.
The authors even observe that walking on an incline on a treadmill burns around 7% more fat than running. Another interesting point for those who monitor their body composition: despite equivalent calorie expenditure, 12-5-30 promotes a metabolism oriented towards fat burning, a serious advantage in a situation of calorie deficit to preserve maximum muscle mass.
How to use 12-5-30 to boost your weight loss
At moderate intensity, such as on a brisk, uphill walk, the body naturally turns to fats, while more intense effort shifts more towards glycogen. This is what makes 12-5-30 a good way to start your weight loss: the effort remains sustained without being exhausting, which helps you maintain the duration and repeat the sessions over the long term.
In practice, not everyone starts with 30 minutes at 12% incline. You can start with a lower slope or a shorter time, then gradually increase. The main thing is to maintain a pace that is a little breathless while still allowing you to speak, to stay in this zone where fat oxidation is maximum and where the joints are more spared than when running.
What exactly is 12-5-30 training?
The 12-5-30 corresponds to walking on a treadmill set at 12% incline, 5 km/h, for 30 minutes, i.e. an uphill, but gentle, cardio session.
Why can this inclined walk help you lose weight better than running?
For the same calorie expenditure, the 2025 study shows that walking on an incline uses fat as fuel more than running, with approximately 7% more fat burned.
Is the 12-5-30 method suitable for beginners or overweight people?
Yes, because it is a low-impact activity for the joints. You can adjust the slope or duration initially, then progress to the full protocol.
Do you still have to be in a calorie deficit to lose weight with 12-5-30?
Yes, as with all cardio, the session mainly helps to increase energy expenditure. Loss of fat mass occurs if the diet creates a lasting calorie deficit.
