How Losing Weight Affects Your Poo

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Here at MAN v FAT, the number 2 most recently asked question we get about weight loss is how it affects your poo. If you’ve already been losing weight, you may have noticed changes in your bowel movements and had some questions or concerns that you’ve been afraid to talk about, or perhaps you’re about to embark on a weight loss journey and want to know what to expect. If so, read on but please note that this article does discuss poo in fairly graphic detail – if that’s not your thing, then maybe read about how weight loss affects your penis instead?

The first thing to say is that if you have any concerns about your poo or anything unexpected you’ve seen in a bowel movement, get off this page – you know, after you’ve bookmarked it to come back to later – and seek medical advice. Don’t just add “go to docs” onto your long list of things to do, actually book in an appointment and go and see your doctor.

Please note, if your poos start talking then you should seek urgent psychiatric help.

With that said, let’s crack on.

Never ones to shy away from the big jobs, we’re here to deliver the goods, so drop the kids off at the pool, pull up a stool and let’s talk shite.

Poos are made up of the parts of food your body either can’t digest or can’t absorb, mixed with water, bacteria, mucus, dead cells and fibre. Obviously, this means what goes in affects what comes out, and not just what you eat and in what amounts, but also how well hydrated you are.

There are several aspects of a textbook bowel movement that can change depending on your diet and we’re going to focus on the most interesting, most telling or most fun ones:

  • Frequency
  • Regularity
  • Consistency
  • Buoyancy
  • Shape
  • Weight
  • Volume
  • Duration
  • Composition
  • Aroma

Everybody poops, but we’re all a bit different.

It’s estimated on average that a healthy adult can digest a standard meal in around 2 days; that’s 4 or 5 hours for the stomach to empty and 30 to 40 hours for the food to pass through the colon. The average amount of poo a healthy adult produces in a day is 128g – which you may know if you’re too frequently stepping on the scales (stop doing that!). Don’t be surprised if you deviate from these norms and don’t be surprised to see your habits change as you lose weight.

So, what changes can you expect and what should you be conscious of?

Let’s start with frequency – no, put down your oscilloscope, we aren’t checking to see if you’re cranking out Radio 2. How frequently do you step up to brown alert? If you’re eating more fruits, vegetables, whole grain cereals and breads as part of improvements to your diet, you may have noticed that you’re going to the toilet more frequently. If you’re less into veganism and trying the keto approach, note that diets which are higher in protein often see a decrease in bowel movements – meat and particularly red meat is more difficult to digest than plants. Additionally, cutting down on dairy can decrease how often you poo but also how much you fart.

However often you go, it’s important to roll with it and listen to your body – when you get the call of the wild, be sure to act quickly, as your poo will grow drier and heavier the longer you wait, making it more difficult to pass. The peristalsis wave, a sort of Mexican wave of contractions along your bowel that let you know it’s time to go, can act in reverse if you ignore it. If you used to be able to set your clock by your toilet routine and that’s started to change, it may be down to what you eat as much as when you eat. Exercise can also encourage bowel movements, so if you’re ramping up your gym time you might find yourself keen to hit the lockers shortly after a session.

In terms of changing consistency, loose or runny stools can often be a cause for concern but be aware that this may be down to a high protein, low fibre diet, as fibre helps to bulk up your poo. Ironically a diet low in fibre can also lead to constipation. If you’re eating more soups, which can be very high in fibre, you may start to see your poos get smaller and more liquid over time.

Of course, the more frequently you go, the less each poo will weigh on average, but what else can affect the weight? People who weigh more, including taller people are more likely to produce heavier poos, so as you lose weight, expect your plops to follow suit.

We know eating more fruits, vegetables, whole grain cereals and breads can see you going to the toilet more frequently, but you may also notice an effect on the weight and buoyancy of your poos. A diet that’s higher in fibre can increase the weight of your poo, but can also cause it to float, due to a higher presence of gases caused by fermentation during the digestive process. However, floating poos can also be caused by infection, so keep an eye on this.

I know you like to think your shit don’t stink, but if you’ve noticed it getting more pungent, that can be linked to eating more eggs for protein, more dried fruits, more veggies such as broccoli, cabbage, cauliflower and kale, and even switching to cooking with coconut oil and drinking coconut milk, so if you were hoping it would smell like suncream, bad news. Another possible culprit is excess saturated and trans fats like the ones you get in crisps, bacon, eggs and mayonnaise, effectively ruling out my former favourite lunch. If you notice your poo starting to smell better after cutting down on dairy, it can be a sign of lactose intolerance that may be worth noting.

If you’re taking longer than usual to lay cable, that may be a sign of stress. Generally speaking, you shouldn’t be spending longer than 15 minutes on the bog.

One thing that can be a major cause for concern is spotting blood in your stool, or when you wipe. Of course, you should always seek medical advice in this event, but keep in mind that if you often spend longer than 10 minutes on the job, you may be developing haemorrhoids, which can be caused by straining, or even the effects of gravity as the unnatural seating position causes your rectum to be lower than your cheeks, causing blood to pool and clot. Piles can bleed, so this may be what you’re seeing. Regardless, if you see blood then get to your GP.

Have you noticed any changes in your toilet habits as a result of your weight changing? Let us know and be as graphic as you like!


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