text: what does it mean if my stool analysis is  positive for fat? it is also positive for vegetable cells,muscle fibres and starch well fat in stool is medically termed steatorrhoea. this may occur in patients with pancreatic insufficiency which may have resulted from any condition. this results to a reduction in fat digestion so that the fat you take in your diet is not absorbed. the pancrease is the key organ in producing lipase, a fat digesting enzyme. but it may also occur in malabsorption syndrome, short bowel syndrom and bacterial overgrowth. in the absence of any symptom the vegetable cells, fat and muscle fibres shouldn't be much of a concern...it's probably from the food you ate.