the newcastle diet has had data on this for a while.

https://www.diabetes.co.uk/diet/newcastle-study-600-calorie-...

Keto, vegan, high carb, low carb, - it really doesn't matter in terms of creating a significant energy deficit for a sustained period of time - the best diet is one that an individual can adhere to.

https://www.ncl.ac.uk/media/wwwnclacuk/newcastlemagneticreso...