Don't just flush: What your stools can tell you about your health

Don't just flush: What your stools can tell you about your health

[Published on www.1news.co.nz 22nd June 2025]

Call them what you will, your bowel movements can indicate everything from poor digestion to serious health issues, and it's important to pay attention to them.

Be it poo, poop or number twos at your place, going to the bathroom is a very normal, and necessary part of everyday life. Having grown up with brothers, working in nursing homes, hospitals, and the world of nutrition for over twenty years, I am way more comfortable talking about the ins and outs of toilet time than most. Especially given that I now have two young boys who love this topic, and a husband who is happy to partake in toilet banter!

But beyond the crude jokes and ‘who farted’ blame game, this is a really important topic. There’s so much you can learn about your body by being aware of what is coming out of you. Digestive issues, nutrient deficiencies, and underlying health issues can all be picked up by being across what is in your number twos.

First up, what actually is it? Yes, I know it is brown, often sticky and not fun to look at, especially if it is left behind in the toilet after you have flushed, but it is the result of a really clever process within your body to help you get rid of the things you no longer need.

Your poo, or stool if that makes it more comfortable to read, is made up of water, the leftover food matter that is indigestible, bacteria, cholesterol and other fats, some protein and a few other bits and pieces that your body doesn’t need anymore and it normally brown because of the combination of bile (something your liver makes to break down fat) and bilirubin (which is made when your red blood cells are breaking down). So, although it doesn’t look good, a brown stool is a good thing!

If not brown, then?

Brown is good, other colours, not so much - although sometimes there's a clear explanation, like the time my son consumed a large amount of blue icing at a birthday party, but let's not go there!

Black: If you're on iron supplements, you will know this one well. You might get frightened when you first see it, but this is quite normal in this situation. Other medications can also make this change, so if you start something new and quickly notice a change, this is likely related. Black, however, can also be a big red flag as it might indicate bleeding in the upper digestive tract. That can be a symptom of a few different things, including bowel cancer. So black stools are something to be across and get checked out .

Green: If you've devoured a batch of green soup or tried to keep up with your garden's overproduction of spinach or silverbeet, this can be a logical explanation. But if you haven't been smashing green veg or had green food colouring recently, this another one to get checked out as it can represent underlying health conditions.

White, clay or pale: This indicates an issue with fat digestion and absolutely needs investigating. Your bile duct could be blocked; you may have other liver problems, and this could also be a sign of coeliac disease, especially if combined with a bad smell and other digestive issues. So don't let this one slide if it is an ongoing issue.

Red: If you've eaten a lot of beetroot or tomatoes, this one can be explained the day after, but other than that, red is not normal. I cannot emphasis this highly enough. If it is fresh blood that you are seeing, it could be haemorrids or bleeding in the lower digestive tract, which again can be a sign of a few conditions including bowel cancer.

As many people in New Zealand die of bowel cancer as breast and prostate cancer combined, so if you find blood, be it dried or fresh, see a doctor. Bowel cancer is 90% treatable if found early, so do not wait.

Consistency and shape

While it is normal to have some variation based on normal fluctuations in what you are eating and drinking from day to day, how stressed you are and (if you're menstruating) where you are in your monthly cycle, poo being very hard, very loose or flip flopping between the two ends of the spectrum is definitely something to explore.

In the health world, we tend to base our views of what is healthy or not on the Bristol stool chart.

Hard, lumpy, or pellet like: This suggests constipation which is likely to be caused by inadequate fibre and/or not drinking enough fluid, it is also more common if you are sedentary.

Oily, greasy or hard to flush:This is a sign that your body isn’t able to absorb nutrients properly, especially fat, and needs looking into.

Diarrhoea, loose or watery: Short term, if you have a bug and aren’t well, this is normal - but if it is ongoing or you flip between these and hard stools, there is likely something going on! Gut infections, food intolerances, endometriosis, Irritable bowel syndrome (IBS) or other digestive issues could be playing their part. Talk to your doctor or Registered Dietitian or Nutritionist about this.

Flat: This may mean that your stool has been squashed as it is passing through, which could suggest narrowing or obstruction in your colon (large intestine).

Presence of mucus: This isn't normal and may be a sign of infection, inflammatory bowel disease, or other digestive issues.

Visible food: While we have all seen corn ‘reappear’, if you are regularly seeing food is a similar form to how it went in your mouth, this is a sign that you might not be chewing your food well enough. That means your body could be missing out on the valuable nutrients it contains.

How often?

Once or twice a day is common for most people, but you might be someone who has always gone every two days and that's normal for you. Going more than a couple of days without a motion is something that needs to be looked into, especially if combined with a hard stool which isn’t easy to pass as you might need to make some dietary or lifestyle changes to get things more regular. It is not normal to need to push so hard your face goes red!

The main thing to be aware of is a change from your ‘normal’. If you have always been a once-a-day person, for example, and start to go several times a day or don’t go for a week and a new pattern persists without obvious explanation, there could be something going on and it’s time to see your doctor.

Other red flags

As well as unexplained colour changes, blood, floating oily poop and unusual changes in your bowel habits, other things to be aware of as a sign of something being not quite right in the digestive department is severe persistent or periodic abdominal pain, a lump or mass in the abdomen, tiredness, or loss of weight for no reason.

Excessive gas and looking six months pregnant after eating, also, is something to get help with.

Despite the fact this topic might feel really uncomfortable for you, rest assured doctors, nurses, dietitians and nutritionists like myself and my team talk about this stuff day in day out and don’t find it remotely embarrassing, so please reach out if you are concerned. You shouldn't have to suffer.

If you have medical concerns, you're advised see a GP or other qualified medical professional.

Here’s a link to this article on 1news.co.nz: Don't just flush: What your stools can tell you about your health

More info: If you would like personalised advice to help understand your symptoms or concerns around gut and digestive health, my team at Mission Nutrition would love to help.