A bowel motion of 150 grams would have a length of about 15 cm (6 inches).
Fecal mass is generally linked to diet. People who eat more fiber usually defecate 'turds' with greater fecal mass. Fiber is found in many natural foods (such as leafy vegetables) as well as dietary supplements. Because they usually eat more fibre than western people, many non-western people have 'poos' with greater fecal mass than western people. It is generally believed that diets high in fibre may help to reduce the likelihood of colon cancer.
Since some people 'poo' more than once a day, fecal mass can also be measured by the average weight of 'poo' passed each day.