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I've heard people say this before; that eating less shrinks your stomach, making you desire less food in the future. When I looked it up online just now, the first few results conflict:

Eating less shrinks the stomach:

Among the dieters, gastric capacity was reduced 27 percent to 36 percent, on average, depending on how it was measured. There was no significant change in the control group.

Eating less has no effect:

Answer: Myth. Once you are an adult, your stomach pretty much remains the same size -- unless you have surgery to intentionally make it smaller.

Eating less makes your stomach bigger:

Absolutely not!

It’s more lkely to distend your stomach and cause you to gain weight.

So what's the truth? Does it actually cause your stomach to change size? Does it actually reduce your appetite? Is there actually a direct connection between stomach size and appetite?

Oddthinking
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endolith
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    From personal experience, I'd say that it does in fact seem to reduce your appetite after a while, by whatever mechanism (perhaps stomach physical shrinking, or body simply getting used to it and sending fewer signals, etc). I'd like to see some actual research about this topic, however. – Daniel B Nov 21 '12 at 07:35
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    Another anecdote: I was in the hospital a couple of years ago and did not eat solid food for two months. (I was "fed" through an IV.) Once I had recovered enough to eat again, my stomach capacity was very low - I remember having two scrambled eggs for breakfast (and nothing else, hadn't eaten for 8-10 hours) and I couldn't finish them. Obviously I can't say for sure whether my stomach was physically smaller than before or if my body decided to give me the "you're full, stop eating" signal far earlier. – Graeme Perrow Nov 21 '12 at 18:15
  • Yep, I'm asking because lately I anecdotally feel sickly full after eating an amount that normally wouldn't bother me. – endolith Nov 21 '12 at 18:38
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    I note that the third link is talking about eating less *for one day*, which seems unlikely to be sufficient to trigger significant changes in organ size. – Oddthinking Nov 22 '12 at 13:23
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    Not an answer, but interesting: This [study](http://www.ncbi.nlm.nih.gov/pubmed/11790438) compared bulimics to obese people and it suggests gastric capacity is related to how much you binge, rather than body weight. – Oddthinking Nov 22 '12 at 13:25
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    Regarding appetite, the mechanism for that as it relates to the stomach (when the stomach is physically stretched, it triggers the body to *stop* producing the hormone that communicates hunger) is touched upon here: https://skeptics.stackexchange.com/questions/35330/does-it-take-time-for-the-brain-to-realize-that-you-have-eaten-too-much/35331#35331 – PoloHoleSet Jun 29 '17 at 16:10

1 Answers1

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We can learn some things about the stomach from competitive eaters.

Competitive eater Joey Chestnut trains his stomach to expand:

Chestnut practices by drinking up to a gallon of milk in a single sitting, which he says trains his stomach to expand.
http://www.webmd.com/food-recipes/features/competitive-eating-how-safe-is-it

Competitive eater Sonya Thomas also says her stomach has been trained to expand:

My stomach is really normal size, but over the years it has been trained to stretch quite a bit.
http://www.sonyatheblackwidow.com/id2.html

From Huff Post, which references Dr. David C. Metz, a published gastroenterology professor:

Our hypothesis became that [competitive eaters] have the ability to relax their stomachs to such a degree that they can just eat and eat. While eating, the average person's stomach may expand to hold two or three liters, he imagines, whereas a competitive eater's may expand to hold six or seven.

There isn't a lot of research around this, and Dr. Metz's study is one of the most cited studies for competitive eating (according to the Huff Post article).

From this limited information, I can only hypothesize that if a normal person's stomach expands to about three liters and a trained competitive eater's expands to seven liters, it's possible that a stomach can lose some stretching capacity when one eats less food.

Either way, it's important to make a distinction between the size of the stomach and the capacity of the stomach. Even if gastric capacity was reduced (as cited by the OP), that may or may not have any impact on the size of the stomach.

Laurel
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joulesm
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    {{citation needed}} – endolith Nov 20 '12 at 16:54
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    Welcome to Skeptics! [We require answers to reference every significant claim they make](http://meta.skeptics.stackexchange.com/questions/5/faq-must-all-answers-be-referenced), please update your answer and add references to support it. – Mad Scientist Nov 22 '12 at 08:51
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    sorry all!! newbie here. I updated my answer with citations and reworded to sound less authoritative. Thanks for the feedback. – joulesm Nov 22 '12 at 10:36
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    @joulesm: This edit makes it a much better answer for Skeptics. Thank you. However, the problem now is the speculation. I heard (with no evidence!) that when you gain weight you grow more fat cells, but when you lose weight, you don't lose the cells, they just become smaller (allegedly making weight re-gain easier). I don't know if it is true, but it suggests that it isn't sufficient to assume that the process of growing your stomach is bidirectional. – Oddthinking Nov 22 '12 at 13:13
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    I see your point. Would it be better to remove the hypothesizing paragraph? Or is there a better way to post evidence that doesn't quite answer the question yet? :) I'd put it as a comment on the OP but I don't have global commenting privileges yet :P – joulesm Nov 22 '12 at 13:55
  • This answer is useful as is, but theoretically answers whether stomachs shrink. I've undeleted it simply because there isn't a better answer at the moment. –  Mar 10 '22 at 15:59