The numbers, according to research source, vary, but one paper I recently read suggested the following:
The thermic effect of protein is about 20-30% of intake.
The thermic effect of carbs is about 5-10% of intake.
The thermic effect of fat is between 3-5%.
So, eat 300g protein (1200kcal) and it costs 240-360kcal to process.
Eat 300g carbs (1200kcal) and it costs 60-120kcal to process.
Eat 300g fat and it costs 36-60kcal to process.
These are not small differences.