I've had similar issues with belching before, and it turned out I had an Ulcer (H. Pylori Infection).

You can pretty quickly get a breath test done at one of those cheapo lab clinics, but also after I got that test I went to a GI doc and did an endoscopy and there was some underlying acid reflux that I'm still figuring out how to handle.

Concentration also causes less energy to be sent to the digestive system because the energy gets diverted to the brain. Concentration is an evolutionary 'fight or flight' adaptation. Therefore when you are highly concentrating, its possible that your digestion gets impaired. Couple this with shallow breathing, then you would have even less energy available for digestion.

Which causes the food to be badly digested, leading to gas and even various syndromes that cause irritation & inflammation in the intestines and even the body in general. Because when a non-digested piece of food enters the intestines, the body can easily trigger the immune responses of the body, thinking that 'a foreign substance has entered the digestive system' (which is natural). This kind of digestive problems, IBS etc seem to be common in tech circles.

"I'll just eat at my desk."

You don't know the harm you're doing!

Sounds like you have gerd - caffeine relaxes the lower esophageal sphincter. Stress significantly aggravates GERD.

For burping there's both the physiological and psychological component involved.

There's been a number of studies about various breathing exercises you can do that will reduce this.

There's one where you put your tongue behind your teeth, open your mouth slightly and breathe, trying to emphasize breathing using your diaphragm. I'll try and find that study for your later.

Here's a similar one.

https://www.cghjournal.org/article/S1542-3565(17)31307-1/ful...

There was also a hacker news article recently about exercises you could do to strengthen those muscles which I'm only starting to try myself.