Fitness

You can.

It is called body recomposition. A lot of people do it.

The problem is that while it is arguable more or less efficient than bulking or cutting, it is a psychological difference.

During a bulk & cut, you see massive differences on both the scale and your body in a short amount of time. That gives a ton of motivation and makes for good progress photos.

If you gain 5 kg mass, some fat, some lean in 6 months then lose 5kg mostly fat, some lean in 6 months for a total of 4kg lean muscle you will see much bigger differences than if you stay the same weight but trade 4kg of lean muscle for fat in 1 year.

Seeing the change is extremely motivating for most people and motivation and discipline are the two most important factors on fitness. They are what help you stick to your diet and training regime.