Studies have shown that about 2 million years ago, humans began to use stone tools to process food, such as cutting meat and smashing plants. At the same time, humans gradually evolved to form smaller teeth and face shapes, as well as weaker chewing muscles and biting power. Therefore. Researchers speculate that the use of tools weakens the power of chewing, which leads to changes in the shape of human faces.
The statement 'The type of human food changed 2 million years ago, which accelerated the change of human face shape' would most weaken the above-mentioned researcher's point of view.