The film is based on the premis that the absolute amount of carbohydrates needed for life is zero. Of course, nothing is definitive, it's just something else to add to the knowledge-base so we can make our own decisions or do more research. Here
The same group are currently doing a 500km fasted cycle ride. https://twitter.com/_healthresults/status/1525386219676483584?s=21&t=xJ4ziY7umL4WrzW3YPE2DQ