I had the exact same issue and did a little write-up for my therapist who was thinking it (at least partially) may have to do with stress and anxiety. It is long and all over the place.... but may be useful to some. Here goes nothing:
- The issue of lightheadedness is light dizziness after the first or the second bite of eating. It is NOT after the stomach starts digestion. It is instant! It had this for months last year and a few times this year.
- It is not blood sugar related, I checked my sugar often and have no issues with blood sugar.
- It is not after a meal, where blood flows to the stomach to digest, the lightheadedness is instant... sometimes as early as chewing the first bite.
- I mentioned this to my PCP and was dismissed. The GI doctor also shrugged his shoulders. The cardiologist made me wear a heart monitor for two weeks and I logged symptoms in a log. It turns out I do have occasional PVC (premature heart something something) but that is common and not significant enough to require treatment. The data collected by the monitor provided NO correlation to my eating lightheadedness and the log.
- I am not alone! Check out this thread I found of people describing the same symptom I had on and off over the last year (ignore the initial replies but see how many people later posted "me too" and no one knows why). It is 25 posts long. Please read through it all if this topic is important to you: www.mumsnet.com/Talk/general_health/2977349-Dizziness-WHEN-Im-eating-drinking
My special circumstances and personal, layman, insights:
- I do have somewhat low blood pressure. I am at 115/80, HR70. That is slow for my weight, size, and sedentary lifestyle. I got this from my mom. I don't believe that BP is very significant for this issue though because I never had the "first-byte dizziness" before in my life. It may play a role.
- Anxiety/depression/panic disorder was often blamed for my physical problems... I started to notice early though that my GI played a role...
- I, for months, theorized that the dizziness was caused by my body "telling me" not to eat. I theorized this because I was getting old and my unhealthy lifestyle was catching up with me at age 47. Now that there is a gallbladder involved, I feel even stronger about my theory that my body didn't want food intake and it was telling me so through lightheadedness as soon as starting to chew the first bye.
- I did see a correlation between how (un)healthy the food is and the lightheadedness. the prime example is the night before I went to the ER and kept for 4 days in April... we actually had pizza the night before and I remember feeling bad eating it! I don't recall the dizziness per se but I recall feeling that I am doing "something wrong" .. my body felt it.
- What changed in April 2020 when "first-byte dizziness" started is the following:
---- life-changing events introducing initial panic attacks that later settled into increased anxiety.
Gallbladder inflammation/1 inch gallstone, which remained undetected until December 2020. It was detected after I finally got myself together in Nov and asked my PCP to refer me to a gI doctor who ordered the ultrasound and found the gallstone right away.
If you have someone you care about suffering from this strange first-bite dizziness, humble me recommends:
- Check blood sugar before and after eating to rule out.
- Log the event (include what the food was and how the person perceived it ( healthy, bad, I shouldn't etc.) and talk to a therapist/psychiatrist/etc. if there is a correlation.
- Consult a GI doctor paying attention to any recent changes in GI behavior/habits. I personally started to have more gas and constipation... it wasn't significant enough in April to be considered but gradually got worse until it was enough in Nov to actually see a GI doctor.
So FOR ME it was gallbladder + increased anxiety is probably to blame.
This is not medical advice obviously... just sharing what I went through in hopes it may help. Best wishes to all.