On the basis that various nomadic tribes use dried cattle dung as a fuel source, poo must retain some calorific value. Correct?

So, for those who count calories, how do you estimate the “calories out” when having a crap?

For the record, I’m not going to weigh my “output”…I’m not that obsessed! 😃

Dry it and see how long it burns?

I think I’m right in saying that any calories in your poo are calories you haven’t actually absorbed, so you couldn’t factor them into actual calories out (i.e. in terms of weight loss). Having a poo is a bit like emptying your pockets before weighing yourself – or indeed having a poo before weighing yourself.

IANAN.

I think I’m right in saying that any calories in your poo are calories you haven’t actually absorbed,

If that’s correct, they shouldn’t be counted as “calories in” either, so how would you account for that?!?

Currently, I’m weighing myself post-poo so maybe I’m overthinking this but just started using My Fitness Pal and curious how their calorie targets work…

I would think that the calories quoted on food (and in my fitness pal) are the calories that an average person can absorb, I.e. excluding poo calories.

That will be one of the reasons that I have to eat less calories than any of these calorie counter things say to lose weight.

Need to leave a couple of hundred calories in my budget to lose weight based on my fitness pal.

What about the Calories expended while on the bog?

Does MFP have activity profiles to suit?
i.e. ‘5 mins moderate straining, followed by half an hour angry birds’ = 8 Calories burned…

At the risk of putting us all of our dinner and all future meals, maybe try to compare it to another food of similar (presumed) calorie density?

E.g. a medium banana (7-8″ is medium apparently, I’d always tried to convince my wife that was “large”… ☹) is 180kCal.

Or 200g* of thick yoghurt like Skyrr mixed with something mostly fibre e.g. fruit like berries or orange or something would also be approx 200kCal?

*yep, I’ve weighed myself pre and post 😂

Also GCN did a great video on this, I think given the number of inaccuracies generally present in calorie counting (e.g. errors in ‘label’ calories in, fitness tracker calories ‘out’) would generally eclipse calories ‘out’ that you might not have counted.

Does MFP have activity profiles to suit?
i.e. ‘5 mins moderate straining, followed by half an hour angry birds’ = 8 Calories burned…

Hmmm, good point. I thought a high fibre diet was good, i.e. virtually no effort required, but no effort is detrimental to the calories expended calculation…
😃

I’d put it down to what is in your guts (oesophagus, stomach, both intestines, bowel) are not actually in you (we are triploblasic after all). It’s just a tube going through you. “Calories in” are only in when they leave this tube, and enter through the intestines into the blood stream

So faecal matter is mostly what you can’t digest (plus dead blood cells etc), and as a result the calorific content may be there, but we can’t use it.

Slight hijack. Did I really expend more calories on my walk than my friend did on his ride?

Strava and other apps always seem way off on calorie burn unless you are measuring power output. For a one hour walk your calorie burn should be around 360 calories. Obviously you would burn more if walking very fast or all uphill. So your Strava calorie burn is way off there.

Zippykona I’m always sceptical of calorie figures but depends on you and you mates weight too and that bike ride looks fairly moderate, cycling can be much easier than walking depending on the nature of the walk. Tarmac is a damn sight easier than rough ground, Heather moor for example. Is it also hr based?

Different animals have different digestive systems.

poo must retain some calorific value. Correct?

It has been thoroughly researched, it has very little nutritional value. Listen to what your mum told you and don’t eat ****.

I often wondered if, heat being energy, cooked food has more calories than raw food.
Yes is the answer it turns out. A small amount more due to the above. Also, a ‘dead’ battery weighs (very, very, very) slightly less than a fully charged one, see E=MC2
A lot more useable calories from cooked food though due to cooked food being much easier to digest and so therefore we can extract a higher proportion of the calories in cooked food than in uncooked.
.
So, what is in your poo? Eat a raw carrot, you’ll get some calories, the poo will have some. Cook and then eat the same carrot, you’ll get more calories and the poo will have less left in it. Just another variable to think about.

Different animals have different digestive systems.

No shit, Sherlock!

Like folks say, there’s not much nutrition in human poo. Also, cattle aren’t people, especially in what they eat and how it’s digested.

dried cattle dung has been used for fire fuel wherever there are cattle and a shortage of better fuels. you can burn it, but you’ll get more heat out of an equivalent weight of wood or charcoal.

I often wondered if, heat being energy, cooked food has more calories than raw food.
Yes is the answer it turns out. A small amount more due to the above. Also, a ‘dead’ battery weighs (very, very, very) slightly less than a fully charged one, see E=MC2

As I understand it, the cooking makes food easier to digest, so your body can extract more calories. It technically doesn’t increase the amount of energy stored in the food.

A battery doesn’t convert mass to energy in the way that a nuclear reactor does. It works by storing and releasing energy through chemical bonds. If it releases hydrogen gas, for example, during that process, its mass will decrease, but if it’s a closed system, it’s not getting heavier and lighter every charge cycle.

Just to muddy the water, so to speak, maybe less than half of you’re poop is remains of food you’ve eaten. Up to 60%, by weight, is your gut bacteria

It technically doesn’t increase the amount of energy stored in the food.

other than hot things having more energy than cold in a general sense It’s not energy we can store – we can’t convert warmth to fat directly. But one of the things use stored energy for Is regulating our body  temp. If you only ate frozen food straight from the freezer and drank ice cubes you’d use stored calories (and therefore offset some calories in the food)  to counteract the cold.

my diet book ‘Convince yourself you’re losing weight whilst eating ice cream’ is available to preorder

Temperature being a measure of average kinetic energy. An energy we can’t convert to a useful energy compared to stored chemical energy in food which we can convert through aerobic respiration, with heat as a by-product.
It’s the usable chemical energy in food that is important. I’m not sure how you measure that. As a bomb would just measure all the energy via E=-mc∆T
Someone must know.

In a related issue and to achieve the best weigh in on Fridays I like to have had a dump before I weigh in. But, often I need a big mug of tea and to be mooching about a bit before the need to go arises. So, I just had a brain wave!

My mug of tea weighs in at a whopping 520g of liquid. I can have that, even two, and just get weighed after my morning cuppa has precipitated the drop, and then minus the tea weight! I feel very proud of this eureka moment LOL!

I think the calories in your poop must be significant as early polar explorers who travelled by dog sled used to supplement the dogs food by letting them eat from the latrines dug by the humans.

I remember being caught short al fresco after having a nice curry the night before. I had to fight my dogs of it while in the act! They obviously though tit was a tasty treat, but then they do with half mummified fish discard and squished rabbit too.

I don’t think that “calories in” is a very helpful way to think about it. I prefer to think of “calories absorbed”. Different people might absorb different amounts from the same input for lots of different reasons, including variations in gut length and the microbes they have in their gut to help (or hinder). Measuring calories in and out is at best a proxy for what is really happening, and while it might be useful for tracking and adjusting on a personal level they can’t really be compared between different people. Or even between in and out. For example, if you’re trying to lose weight you could be putting X calories in your mouth and calculating by whatever means that you’re burning Y calories. If X if greater than Y but you’re loosing weight it doesn’t matter what the numbers are in relation to each other.

I prefer to think of “calories absorbed”

Basically, yes. You could eat (and drink) continuously, but with a dodgy intestine (coeliac? Crohn’s? Diarrohea? etc) you’re not absorbing, and therefore not taking advantage of the calorific content of the food.

Want to lose weight fast? Salmonella works wonders.

Indigestible cpcponents of food are taken into account when calculating food calories. href=”https://en.m.wikipedia.org/wiki/Atwater_system#Modified_system

As above, everyone’s body is different. When you eat, the food doesn’t just go into a big tank and then get emptied when you exercise. A load of things have to work in order to break the food down into different components, mostly bacteria inside your guts. And we all have different bacteria – do you get the farts when you eat beans and cabbage? I don’t.

Then once you have absorbed the energy from your food it doesn’t necessarily just get pushed under your skin as fat. That process is controlled by various hormones, and those levels are different in different people. This is why some people can eat tons and never get fat; it’s also why some people get fat very easily. I know for some people it feels good to look down on fatties for being lazy slobs but it’s not always as simple as they’d like it to be.

Yep, the more I’ve looked into it, the more any figures quoted seem like a fudge (fudge is delicious and calorie dense, btw). I’m told calories are by definition the amount of heat given out when a substance is burned. Fine, I can burn lego and it gives off heat, but when I swallow it, it goes right through (round bits only, please). So a chemist called Atwater switched to counting carbs/protein/fat and weighting them by ratios, about a hundred years ago. These were modified in the 70s for some fruit and veg, but that’s basically the basis for our labels. Some stuff will provide more usable calories if it’s made easier to digest (smoothies, soups, ice cream etc) so adding up the table values for the ingredients really doesn’t work. I’ve seen figures in articles suggesting overestimating calories of some stuff by 25% and underestimating easily absorbed stuff by 55%.

Back to Zippkona’s walk and his mate’s bike ride. If you’re sitting about, you’ll be on 150 cals/hr ish. Zippy goes for one hour, 150kcal. His mate 2, 300kcal. For the numbers to be right, Zippykona needs to be burning 550/hr extra cals abouve resting rate walking and his mate 200. I’m not buying it. I do believe long and slow exercise is incredibly beneficial though, as it keeps you away from the fridge for longer.

WorldClassAccident
Free Member

Dry it and see how long it burns?

That’s a good point. Could you burn a human turd? Somebody try it, for science sake.

So a chemist called Atwater switched to counting carbs/protein/fat and weighting them by ratios

Ok, but hair is made of keratin (a protein) and I’m fairly sure that if you ate loads of hair you wouldn’t get as much nutritional benefit as if you ate loads of beef. So it’s safe to say that that would only be an approximation and it could vary.

On the original question:

3.2.5 . Carbohydrate and Energy Value
The carbohydrate fraction is largely made up of undigested cellulose, vegetable fibers, and pentosan (Canfield et al., 1963). Feces do not contain large quantities of carbohydrates as the majority of what is consumed is absorbed; however, undigested and unabsorbed fractions (RS) remain. A median value (n = 10) of 9 g/cap/day carbohydrate in feces was recorded with a range of 4–24 g/cap/day. The vast majority of studies were again conducted in North America and Europe with only one study in Peru presenting values in the center of this range. The calorific content of feces had a median value (n = 14) of 132 kcal/cap/day (range: 49–347 kcal/cap/day). By using the median value of production (32 g/cap/day) a calorific value of 4115 kcal/kg dry solids can be used as a design standard for calorific value of feces. All studies were carried out in North America and Europe therefore no correlation could be made between income and calorific value. However, the largest quantities of fecal energy are shown from diets containing a large amount of unavailable carbohydrates (Southgate and Durnin, 1970), defined as all polysaccharides not hydrolyzed by the intestinal secretions of humans, as opposed to available carbohydrates such as starch and sugars which result in less fecal energy loss (Southgate, 1973).

– https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4500995/

The experimental results show that the dry human faeces had a higher energy content (∼25 MJ/kg) than wood biomass.

– https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4998016/

I forsee a new peak STW: “What jobbie fuelled stove for the mancave?”

I vaguely remember reading that you can eat your own poo twice, before there is no nutritional value.

A median value (n = 10) of 9 g/cap/day carbohydrate in feces was recorded with a range of 4–24 g/cap/day.

That’s interesting – quite a large range.

We’re told that the typical maximum absorption rate of carbohydrate is 1g/hour/kg lean body weight, but it is entirely possible to eat much more than that. The rest must be excreted, surely?

I don’t think that’s necessarily true. It’ll depend on how long whatever you eat is hanging around inside you before it comes out the other end.

Eat a raw carrot, you’ll get some calories, the poo will have some. Cook and then eat the same carrot, you’ll get more calories and the poo will have less left in it.

Anyone got any recipes for cooking defecated carrot?

Whilst looking at some diet stuff pre-lockdown (LOL) i discovered that you actualy excrete more from exhaling over the course of the day, than sweating or pooping.