Not to invalidate your argument, but clearly people fast for much longer than 4 days without food, for example "At the age of 74 and already slight of build, Mahatma Gandhi, the famous nonviolent campaigner for India's independence, survived 21 days of total starvation while only allowing himself sips of water." [1]

1: https://www.scientificamerican.com/article/how-long-can-a-pe...