Weighing after going to the bathroom- what does this mean to you?
Replies
-
Silentpadna wrote: »
So if you increase the dissolved methane in your system, you would lose weight? I know that can be taken as "snarky", but really not meant to be that. Just trying to understand this reasoning.
Exactly.
And thus defecation/flatulence can result in a higher scale weight.1 -
stanmann571 wrote: »
If poop has mass, which it does, and you decrease the mass of poop in a closed container (your body), your weight has absolutely zero chance of going up.
If methane has mass, which it does, and you let that mass of gas pass (sorry) from a closed container (your body), your weight has absolutely zero chance of going up.
W = MxG, where
W = weight
M = mass
G = gravitational acceleration
G is a constant. If you increase mass (M), you increase weight (W). If you decrease mass (M), you decrease weight (W).
Now, you can argue that the body is not really a closed container, but with nothing else happening other than breathing, you are not immediately replacing any of that lost mass to any significant degree. For the purposes of the scale in this scenario and to the order of magnitude of your mass, your body behaves extremely close to a closed container.
So help me find the flaw in this reasoning?
2 -
Haha, being a bit anal here
3 -
-
Silentpadna wrote: »
If poop has mass, which it does, and you decrease the mass of poop in a closed container (your body), your weight has absolutely zero chance of going up.
If methane has mass, which it does, and you let that mass of gas pass (sorry) from a closed container (your body), your weight has absolutely zero chance of going up.
W = MxG, where
W = weight
M = mass
G = gravitational acceleration
G is a constant. If you increase mass (M), you increase weight (W). If you decrease mass (M), you decrease weight (W).
Now, you can argue that the body is not really a closed container, but with nothing else happening other than breathing, you are not immediately replacing any of that lost mass to any significant degree. For the purposes of the scale in this scenario and to the order of magnitude of your mass, your body behaves extremely close to a closed container.
So help me find the flaw in this reasoning?
Replace methane in your equation with helium.
Breath in a small amount of helium, and trap it in your lungs briefly.... Your weight will go down.
If Methane is as I believe, lighter than air, then it behaves in the same way.
1 -
The solution to the two great mysteries proposed here is the same.
Mystery number one: "I pooped a bunch and stepped on the scale and it was the same as before! What happened, are my poops magically weightless?"
Mystery number two: "I pooped and then weighed again and had gained weight! My poops must be lighter than air!"
No. Your scale is inaccurate by a couple of percent, like every single household digital scale made. It's an unavoidable result of how they are made, and even scales which claim to be accurate to within .2 lbs mention that they are off by a certain percent in the small print. Most scales have a built in memory which hides the inaccuracy by causing the scale to read the same as the last reading if it's within a certain time period and weight.
The person who pooped and noticed no difference didn't wait long enough for the memory to reset on the scale, so since the weight was within a pound of the previous weight, the scale didn't actually weigh her. The way to get around this is to pick up something heavier than one pound, weigh yourself, and then weigh yourself the second time for an actual reading.
The person whose weight went down waited long enough for the memory of the scale to reset, and then the scale's inaccuracy caused the weight to be off by a couple of pounds compared to the previous reading. There's no way to get around this, but if you care, you can weigh yourself several times in a row while resetting the memory by picking up something heavy every other time, you can get an idea of how much your scale varies. Then weigh yourself until you see the highest reading and the lowest reading. Somewhere in the middle is the true reading. Or you can accept that even though any given reading may be off by two pounds, the trend over time will be accurate.4 -
stanmann571 wrote: »
Replace methane in your equation with helium.
Breath in a small amount of helium, and trap it in your lungs briefly.... Your weight will go down.
If Methane is as I believe, lighter than air, then it behaves in the same way.
Ok, let's look at this. Methane and helium are, of course, lighter than air.
The specific gravity of methane is 0.554
The specific gravity of helium is 0.138
The specific gravity of each is their relative density to the same volume of air.
Since the average human lung capacity is 6 liters of air, and 28.32 liters of air weighs about 0.0807 pounds, our lung capacity is approximately 0.017 pounds. Using the specific gravities above, if you replaced the air in your body with helium, you would "gain" the difference between the same volume of helium vs. the same volume of air, or 0.015 pounds. If you replaced the air in your body with methane, you would "gain" 0.007 pounds.
No scale that I know of for weighing in the range of human body would ever pick that up...
But......this is not what you're describing.
In your original scenario, when you expel methane from your body, you are not really replacing it with additional air.
If you are holding your breath (a way of keeping variables constant), expelling methane would reduce mass because that mass is not in the same container anymore. And I'm sorry you can't flow gas in and out in opposite directions from the same orifice at the same time. With that in mind, no matter what the minutia above illustrates, it is still impossible to increase weight while decreasing mass.
You've shown that methane is lighter than air, but not shown that air is replacing methane in the scenario. Sorry I just can't let this one pass....hehe0 -
Silentpadna wrote: »
Ok, let's look at this. Methane and helium are, of course, lighter than air.
The specific gravity of methane is 0.554
The specific gravity of helium is 0.138
The specific gravity of each is their relative density to the same volume of air.
Since the average human lung capacity is 6 liters of air, and 28.32 liters of air weighs about 0.0807 pounds, our lung capacity is approximately 0.017 pounds. Using the specific gravities above, if you replaced the air in your body with helium, you would "gain" the difference between the same volume of helium vs. the same volume of air, or 0.015 pounds. If you replaced the air in your body with methane, you would "gain" 0.007 pounds.
No scale that I know of for weighing in the range of human body would ever pick that up...
But......this is not what you're describing.
In your original scenario, when you expel methane from your body, you are not really replacing it with additional air.
If you are holding your breath (a way of keeping variables constant), expelling methane would reduce mass because that mass is not in the same container anymore. And I'm sorry you can't flow gas in and out in opposite directions from the same orifice at the same time. With that in mind, no matter what the minutia above illustrates, it is still impossible to increase weight while decreasing mass.
You've shown that methane is lighter than air, but not shown that air is replacing methane in the scenario. Sorry I just can't let this one pass....hehe
this made me happy inside. hehe
but I also had to think... just how much gas does a person have to HAVE to have it affect their weight?
What the heck were they eating, too?
and, for science... if said person evacuated all that air into a balloon, would it float?
I NEED TO KNOW.2 -
This thread is just awesome now.4
-
@Silentpadna, you really enjoyed that didn't you
I too would like to know about the balloon, asking for a friend who isn't keen on being the guineapig.
Cheers, h.1 -
Just a statement of fact here:
If my scale shows a two pound loss after I poop... I celebrate. I text my friends. We all rejoice.
Because I am finally not nearly as full of sheet as I used to be!
I refuse to acknowledge the validity of a scenario that suggests the 2 pound loss is just a mis-measurement.
No! It really was that awesome of a poop. I clearly worked hard for that!5 -
middlehaitch wrote: »@Silentpadna, you really enjoyed that didn't you
I too would like to know about the balloon, asking for a friend who isn't keen on being the guineapig.
Cheers, h.
Yeah....a little bit of fun. And, honestly seeing if I'm missing something conceptually. I'm an engineer by trade, but my science stuff like this was learned 30+ years ago and I don't really use it now. I don't know if there is a blind spot here....I know none of this is significant to the thread, but I just couldn't let it go by.
Yes, if you put methane into a balloon - assuming you put enough of it in there, it should float (depends on the weight of the balloon of course).2 -
Scales lie so don't worry too much about the specifics. I've actually had a morning where I weighed more after #2 than before, and I hadn't had as much as coffee yet that morning. WTF? How is that even possible? You lying sack of scales!1
-
- Get up
- Urinate
- Weigh
- Record
- Forget about it 'til tomorrow
2 -
-
Christine_72 wrote: »
This is exactly what I've been doing since starting this thread. A huge and stupidly insignificant stress has been lifted off my shoulders!
I love the fact that you got this much mileage out of a *kitten* thread! That said, I've been hoping to get rid of the 6 extra pounds of poo I've been packing around over the last couple months, it just isn't happening so back to the drawing board. 2 -
I go nuts if I forget to weight myself before I get dressed. There's times that I go back into the bathroom and get undressed to do it. I've weighed myself after peeing and it is around a .2 difference on average but every little drop mentally makes me feel better about myself so I happily take it. Honestly don't think poop weighs that much but definitely can feel the difference after lol0
-
I'll tell you what makes me insane is when I go to the doctors and they weigh me with clothes....shoes and middle of the day sfter breakfast and lunch!
Anymore...I close my eyes and I tell them...dont tell me cause it's bad for my mental outlook
2 -
I'll tell you what makes me insane is when I go to the doctors and they weigh me with clothes....shoes and middle of the day sfter breakfast and lunch!
Anymore...I close my eyes and I tell them...dont tell me cause it's bad for my mental outlook
Kick off your shoes. IME, they won't judge. 0 -
At my last job I had been known to say, " I got to take a dump", I don't say that anymore, I now work in retail...
When I had a scale in my home, I would weigh after poo, and before breakfast, I was/am quite reg. in that I would go within a 1/2 hour of waking, now I don't have a scale at my house, so I just weigh at the gym 1 day a week. The daily fluctuation would drive me batty...0 -
And here I am, looking forward to the day that I will weigh myself with clothes on! ... But kidding aside ... I can relate to the question1
-
I love the fact that you got this much mileage out of a *kitten* thread! That said, I've been hoping to get rid of the 6 extra pounds of poo I've been packing around over the last couple months, it just isn't happening so back to the drawing board.
That is some backlog you are packing around
, h. 1 -
middlehaitch wrote: »
Don't joke about that
Just came off a case of med induced constipation. I'm now 6lbs lighter (after having progressively gained them over the course of 2 weeks).
Also, I'm jealous of all you clockwork regular folks 2 -
-
I weigh before eating in the mornings. I don't care if I've gone poop or not lol. I do pee first though but no meal yet and completely nekkid
0 -
I get up, pee--weigh--make coffee--take a sip or two--walk around a bit--back to the bathroom like clockwork because of the warm coffee--weigh again--record it---done!
And yes, there is a difference in the numbers. For me between .2-.4 of a pound. Beef takes longer to process through the body and usually causes a bigger dip in the number.1
This discussion has been closed.
Categories
- All Categories
- 1.4M Health, Wellness and Goals
- 395K Introduce Yourself
- 44K Getting Started
- 260.6K Health and Weight Loss
- 176.2K Food and Nutrition
- 47.5K Recipes
- 232.7K Fitness and Exercise
- 444 Sleep, Mindfulness and Overall Wellness
- 6.5K Goal: Maintaining Weight
- 8.6K Goal: Gaining Weight and Body Building
- 153.2K Motivation and Support
- 8.2K Challenges
- 1.3K Debate Club
- 96.4K Chit-Chat
- 2.5K Fun and Games
- 4.2K MyFitnessPal Information
- 16 News and Announcements
- 1.3K Feature Suggestions and Ideas
- 2.9K MyFitnessPal Tech Support Questions