[IAmBroom]

"In at least one case cited in the investigation, baking powder was mixed into food to make tourists physically unwell."

The only ill effect I can find from overconsumption is a "tingly sensation on the tongue". Of course, that doesn't mean the 'poisoner' wasn't ignorant of this, and genuinely did it trying to make them sick. Or maybe they simply said, "If you feel your tongue tingling, YOU ARE DYING!!!".

[ceejayoz]

It’s a leavener when you get it wet, so swallowing enough will definitely feel like digestive upset from all the gas.

[tokai]

Baking powder is used by some athletes as it is shown to enhance performance.[0] I find it more realistic that they are adding it for that effect than making anyone unwell. As its not really something that makes you ill.

[0] https://pmc.ncbi.nlm.nih.gov/articles/PMC8427947/

[KaseKun]

I saw a good yt video on this the other day, investigating baking soda and athletics. https://youtu.be/Y_aTfQmqc5o

The creator certainly got pretty crook from ingesting baking soda

[ambicapter]

I feel like "make physically unwell" here just means they'll taste something gross, not realize it is the baking powder, and treat the feeling as if something is wrong with their body. I know mixing up baking soda and baking powder has made for some pretty unpleasant tasting food for me.

[MontagFTB]

Could it be a symptom of high altitude oxygen deprivation?

[datadrivenangel]

Yes, which is why it's easy to then convince people to evacuate. People do die on Everest, including EBC treks from altitude sickness alone, so severe symptoms usually lead to taking the trekking back down the mountain.