If you eat 10lbs of food would you weight 10lbs more on the scale?

A bunch of us were having an eating contest and the topic was brought up that we should weigh before and after to see who ate the most.

I suggested that there isn’t a 1:1 relationship in the weight of food because food has a lot of water in it and that people sweat and it evaporates throughout the meal.

My question is, if someone doesn’t sweat or urinate, is there a 1:1 relationship. 1 pound of food in equals 1 pound on the scale.

And if there is a 1:1 relationship, is there enough perspiration during a competitive eating event where weighing before and after would be a reliable way to determine the biggest eater?

Briefly, at least until you ended up in the emergency ward of the hospital.

That rather depends on the accuracy, or, more importantly, resolution of your scales. And the temperature and other conditions in which you are eating.

For normal conditions it’s unlikely that a set of scales of the type that are typically used to weigh humans would have a high enough resolution to register the weight lost by sweating.

Yes thats true about scales. Both my cats are over 10 pounds weight, but if I want to weigh them I have to get on the scale with them. Then I weigh again and subtract my weight.

The minimal weight that registers is in the neighborhood of 10 pounds.

Yes, there are industrial scales that measure in grams and micro-grams that would be accurate enough for eating competition. I believe there would be complications with cheating and you would need to weigh the people naked to prevent scams though.

If you put it in your mouth, it will weigh you down. The extra weight won’t stick around after you digest it. A three or four day average would give a better picture of true weight. If each EXTRA(compared to metabolism) pound taken in had 3500 calories, theoretically, you would add pounds on a 1:1 basis except such extreme calorie intake would not efficiently be absorbed. The weight gain would be substantially less.

If someone doesn’t sweat or pee (and if you account for the miniscule amount of moisture exhaled with each breath), then yes, eating one pound of food will make you one pound heavier.

OP claims food has a lot of water in it that gets extracted by the body, but I think the opposite is true: food is generally drier than ideal for digestion, so eaters will drink liquids while eating to help wash food down. Example: watch footage of Kobayashi eating hot dogs, and he basically dips the bun in water to soften it and make it slide down easier. Liquids taken in during a short-duration eating contest (ten minutes?) will overwhelm the amount lost to perspiration during that same time interval.

That’s one problem. As Al Bundy notes, another problem is the accuracy required of the scales used to weigh competitors. If a 200-pound contestant wins by eating a 1/4-pound more than the other guy, then the scale needs to have a precision of one tenth of one percent. There are scales out there that are accurate enough to do this, but they ain’t cheap.

Rather than weighing the contestant, it’s far easier/cheaper/more accurate to just weigh the pile of food before and after the contestant has eaten his fill.

I agree, for normal conditions and a reasonable length of time, etc. etc. So a half-hour meal at comfortable room temperature, I don’t think water loss will matter.

Also pointing out that under comfortable conditions, probably more water is being lost through breathing than sweating (but again not enough to matter over half an hour or so, at least compared to a five-pound meal).

Theoretically, as your body metabolizes the food to energy, a tiny bit of mass is lost (E=mc^2 and all that), but of course that’s not really detectable by any available technology.
[Also noting that you need to tighten up the rules of your competition, since you forbade urinating, but not bowel movements].

Competitive eaters will drink a significant amount of water (or wet the food) to make it easier to swallow. They would gain more than 10 lbs eating 10 lbs of food plus the water they consume. Any loss through sweat wouldn’t be significant.

As a side note, the body’s primary excretory organ, by mass of material excreted, is actually the lungs. You’ll lose more weight by exhaling carbon dioxide than you will by sweating, peeing, or pooping.

It’d be pretty cool if i’m wrong but I don’t think it works like that. Food energy is chemical energy, energy stored from some other process such as photosynthesis. none of the matter in the food is converted to energy.

If energy was basket making supplies you could weave a basket. The basket would be matter, and you could later transmute part of the basket back into basket supplies, this would be like fission or fusion or something. That’s what I think you’re thinking of.

However you could also put basket supplies in the basket, that would be like chemical energy, or some other kind.

In otherwords atoms can be made into energy, but they can also carry energy. Life as we know it uses the energy that’s carried.

I am not highly qualified in this area but energy and mass are equivalent, thence E=mc[sup]2[/sup] (and all that). When energy is released from chemical bonds, the mass of the remaining matter does decrease, according to that famous equation. However, we’re not turning electrons or protons into energy here. But it’s a very small amount compared to off-gassing of CO[sub]2[/sub] and so forth.

Yup, you are wrong. Chemical reactions result in mass change. The mass change is so small as to be negligible though.

Ayup, energy is energy, whether you’re storing it in nuclear bonds (liberated by nuclear reactions) or electronic bonds (liberated by chemical reactions).

The mass change is indeed negligible, unless we’re dealing with a whole lot of mass to begin with. The space shuttle, in burning 1 shitload of hydrogen with 1 shitload of oxygen during its ascent, produces 1 shitload of water. The resultant shitload of water weighs a couple of grams less than the original shitload of hydrogen and oxygen; that missing couple of grams is manifested as 1 shitload of heat liberated by the main engines.

Nitpick: It’s two shitloads of hydrogen burned with each one shitload of oxygen, to produce two shitloads of water.

2 SH + 1SO = 2SH2O or 1 SH2O?

Since no one else has done it yet, and I understand that it’s obligatory, this little detail was covered by Señor Adams himself: Does an airplane weigh less after the passengers have eaten their meals? - The Straight Dope.

ISTM that in the short term, if you eat 10 lbs of food, you gain (close enough for government work) 10lbs. Just as if you had picked up a 10 lb dumbbell.

Much beyond that, however, keeping the books on gains and losses is going to be a nightmare.

Complicating factors are that a startlingly high percentage of poo is made up of shed cells from the bowel walls. Those shed cells, of course, were constructed of food previously eaten. So a question to be answered is, how much of each meal finds its way into poo (and you can’t just weigh the poo to find out).

Next question is the extent to which the proportion of food which is absorbed remains at its original weight. We breathe oxygen so that it combines with all the busy chemicals in our bodies, which all originally come from food. I can well imagine that 1 g of absorbed food becomes (say) 1.5 g of added weight when it is combined with oxygen from the air and sits on our hips.

What with the constant inputting and outputting of mass and the chemical chicanery going on, I suspect it is impossible meaningfully to trace what happens to an individual meal in order to answer the question much beyond the very immediate period after eating. But I’d love to know.

It would be 2 SH[sub]2[/sub] + 1SO[sub]2[/sub] = 2SH[sub]2[/sub]O

That was my first thought reading the thread title too: you’d probably gain more than 10 pounds since you’re going to have to drink something, and water is heavy.

I don’t think the extra oxygen comes into the process until the food is metabolized and releases energy. You put gasoline in your car and it stays in the tank as gasoline, stored until it’s needed. The car sucks in air to support the combustion as it happens, then the waste products find their way out.