My apple watch has alerted me to the fact that if I eat a really salty meal- like a burger and fries, or a whole bag of kettle chips- my heart rate increases by about 40 beats per minute. It's like "Hey... you don't seem to have moved and your heart is going bananas. You ok bro?"
Or just be dehydrated. Salt dehydrates you and most people are already mildly dehydrated at most times. Dehydration can do a lot of shit to the human body, hydro homies wasn't just a joke subreddit!
For me, I can take chips on an empty stomach all right around breakfast time (not that I would generally want to). Later in the day, if I don't eat protein or fat before eating the chips, I'll get a headache and joint pain. In the evening, I'll often get pain regardless of what I eat.