Almost no one thinks about it while flushing the toilet.
According to a scientific review published in 2015 in the journal Critical Reviews in Environmental Science and Technology, a person produces a median of about 128 grams of feces per day. Over the course of a year, that amounts to nearly 47 kilograms per person.
The research, conducted by Rose and colleagues using data collected from numerous studies, also showed that the amount can vary considerably depending on diet, especially fiber intake. In addition, about 75% of the weight of feces is water, while the rest consists of bacteria, fiber and other undigested matter, minerals, and cells naturally shed by the body.
Although it is not exactly the most glamorous topic, feces can also provide information about nutrition, the microbiota, and intestinal health, and studying them is important for understanding and designing sanitation systems.