Guest Post: Dr Richard Krysztopik explains the medical process behind eating.

Sometimes it pays to know how the eating process works. For regular competitive eaters, there are a raft of complications that can occur. We talks to Dr Richard Krysztopik, a consultant surgeon working at the Royal United Hospital Bath, specialising in Bariatric treatment and “Minimally invasive (key hole) surgery, including operations for gallstones and abdominal wall hernia repair, Gastro-oesophageal surgery, such as key hole surgery for hiatus hernia repair or reflux control, achalasia and obesity surgery”. We asked him some about some of the medical and scientific factors that ought to be considered when embarking on an eating odyssey*

“The human stomach can typically hold, depending on age and the size of the human being, around about a litre in volume. It’s obviously smaller in a child or a smaller person and correspondingly larger in an adult or larger framed person. 

In terms of an anatomical measure of volume (in terms of function) it’s about how fast you fill the stomach and with what substance. As part of the gastrointestinal tract, the stomach is part of a complex system; the first chamber. Food is stored and prepared before passing on to the intestines. Depending on what you’ve eaten (and how you’ve eaten it), this process might be very brief (sometimes a matter of moments) or it could be a lot longer. For example, liquids will pass through very quickly through the stomach and intestines, so sometimes it’s very difficult to maintain a litre of liquid in the stomach.

Feeling “full” is a quite a complex thing. It’s not purely a physical reaction. It’s not centred entirely on the stomach itself. The majority of the sensation is mediated by neurotransmitters in the brain. There are messages coming to the brain in many formats, so before you even start eating, the smell of the food, how it looks, the company you are in, the mood you’re in; all these things will influence how you feel when eating that food and whether you are satisfied or not.

It’s a blanket statement that you can apply to any individual but the mood that someone is in can influence how they feel about food. It can influence either way. A typical example might be people who are nervous or agitated might not be hungry and may feel nauseated. At the other extreme, there are well known associations with a low mood and a depressed mood, people find comfort in eating and enjoy the physical sensation that food is giving. It changes the brain chemistry and causes them to not feel as low or depressed. When it comes to analysing eating disorders, they are very difficult to unravel. Often the stomach is a relatively unimportant part of that process.

The stomach itself does have some crude sensation towards different components of food, so it will sense whether it’s breaking down carbohydrate, protein, or fat, and convey those messages accordingly to the brain. At the extreme, there are “stretch” receptors in the stomach, which doesn’t always happen when the stomach is full. Its part of a general process when the stomach has a lot in it, typically gas.

Vomiting is quite a structured process that involves muscles contracting in a certain way, the larynx, the back of the mouth, the voice box, the abdominal wall muscles contracting very vigorously. In the same way the stomach itself contracts in such a way as to close the exit to the stomach but leave the entrance open.

It’s difficult to injure the oesophagus or stomach from eating too quickly or too much but if the process of peristalsis (where food is squeezed in the throat for a few seconds) is overwhelmed for a few seconds, then there would be an immediate feeling of discomfort. Once the stomach gets very full, and if you ignore every biological response telling you to stop eating (which is very rare), there are some rare instances where the stomach can be perforated.

The interesting thing about spicy food is that it isn’t actually very toxic. Chilli, the best known example, simply contains a chemical that switches on a very specific neural-receptor in you gut and mouth. The only reason it tastes hot is that it’s tricking your tastebuds into feeling heat (there is none, there is no temperature change at all) but the chemicals bind to the responding receptors in your tongue, until the protein chain breaks down and you feel normal again. In itself, it’s not going to cause any damage. There are rare occasions where people are allergic but in terms of spices themselves, they aren’t particularly toxic. The gut doesn’t especially like handling them, which can lead to…increased bowel transit.

In my experience, ailments or injuries from this kind of eating, is usually incidental to what is being eaten. We receive people in hospital in an emergency where people have been to these events, vomited on a fairly full stomach and damaged the oesophagus but it’s rare. In most cases, it’s not the compositional content of the food that causes a problem but the process (and complications) of eating itself.”

Photo permission: NHS Bath / interviewee’s own.

* None of the above should be taken as declarative medical advice. Always seek a professional medical opinion if you are ill.



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