Sadly dining etiquette has been somewhat lost and, whilst it doesn't change the nutritional value of the food you're eating, it does make the experience altogether more pleasurable for all at the table if the basic rules are followed as well as aiding proper digestion. So, at the risk of sounding somewhat like a house mistress, here they are:
First up is not eating til everyone, particularly the chef, is seated and served - not a rule always observed at West family gatherings! Not only is this polite but it gives everyone a little breather to relax before they start eating instead of rushing into eating whilst their bodies are still in stress mode.
Sitting tall and keeping your elbows off the table - this encourages good posture which doesn't just look good but is also good for digestion. If you're hunched over then blood flow will be reduced to your abdomen and your food won't pass through your intestines as easily as they should.
Don't talk with food in your mouth - combining talking and eating can cause you to swallow air and usually means you won't be chewing your food properly. Alternating between the two gives you a break between mouthfuls, slowing down your intake of food. Most of us eat too quickly so it's also good to get in the habit of putting your knife and fork down whilst speaking or chewing to slow the pace right down. Equally out of courtesy try and avoid directing questions at a fellow diner when they are mid mouthful!
Don't overload your fork - shovelling in huge fork fulls of food isn't just super unattractive, it also makes it pretty tricky to chew properly meaning you're likely to swallow food that isn't sufficiently broken down. This can lead to incomplete digestion and uncomfortable stomach symptoms such as cramps and bloating.
Always eat with your mouth closed - I'm pretty sure all NITC readers will be polite enough not to eat with their mouths open, but for anyone who doesn't that's another sure way of swallowing air leading to hiccups/indigestion.
Offer any communal dishes around the table - this isn't just good manners but if you're entertaining also means you're less likely to be left with a big pile of leftovers that you feel compelled to eat your way through.