Narrative:

While walking through the airport; I stopped at an airport cafe and purchased a 'protein pack'. This consisted of a small amount of grapes; cheese; walnuts; and a hard boiled egg. [We] departed without incident. Once at our cruise altitude; I decided to have a snack and started eating the contents of the 'protein pack'. Approximately 2 mins after first bite of the food; I began to have an upset stomach and figured I'd just need a restroom break at some point. I [notified] the captain that I didn't feel well and that my stomach was upset. I initially thought I'd be able to wait until after fas finished servicing passenger. The upset stomach became more painful cramping and I began getting nauseous. I told the captain I couldn't wait any longer and needed a break as soon as possible. I got up out of the seat to wait for fas to setup break and felt very lightheaded; nauseous; was sweating; got tunnel vision; and ultimately fainted behind the pilots' seats. I woke up within 5-6 seconds; declared that I was okay. Opened the flight deck door and prior to entering the lavatory fainted twice while being assisted by flight attendant. I again was up after a few seconds still with severe stomach pain so entered the restroom to attempt to relieve myself. I wiped my forehead with a cold towel and asked flight attendant for some water. The crew were able to find a neurologist to assist. I exited the lavatory and the doc asked me several questions such as my name; where we were coming from; where we are going to; type of place; dob; etc. Additionally he checked my vitals which were normal. I told him what happened and he was 100% sure it was not a seizure; and believed that the food poisoning caused the severe stomach cramps; which in turn caused my pulse and blood pressure to fall below a certain point to cause a vasovagal response. [The] dr. Also noted due to me being physically fit and a runner my resting heart rate; blood pressure; and pulse is very low and it is very common for athletes to have vasovagal responses due to this. My stomach was still a upset so I went back into the lavatory to force all of the protein pack out of my stomach. After that; I felt 100% and went back outside and chatted with the dr and fas then returned to the flight deck. [A F/a] had been in the flight deck with another F/a while I was being looked at. We were already descending in the mid 20s towards [a divert airport] by time I got back into the seat. A deadheading [pilot] identified himself to the crew and joined us in the flight deck. The captain and I discussed a plan for the arrival. Since there was still a lot of coordination to be had we both felt comfortable with me flying and him finishing up all of the coordination and checklist. Flew the ILS 34L for a uneventful landing. Once at the gate; I exited the aircraft and met with emt personnel. They checked my vitals; blood sugar; as well as checked my heart and everything checked out normal. I explained what happened; and they agreed that the condition was a vasovagal response caused from cramping due to possible food poisoning and that I was fine.

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Original NASA ASRS Text

Title: B757 flight crew reported the FO became ill during the flight and experienced several fainting episodes. The flight diverted to an alternate airport for medical attention.

Narrative: While walking through the airport; I stopped at an airport cafe and purchased a 'Protein Pack'. This consisted of a small amount of grapes; cheese; walnuts; and a hard boiled egg. [We] departed without incident. Once at our cruise altitude; I decided to have a snack and started eating the contents of the 'Protein Pack'. Approximately 2 mins after first bite of the food; I began to have an upset stomach and figured I'd just need a restroom break at some point. I [notified] the Captain that I didn't feel well and that my stomach was upset. I initially thought I'd be able to wait until after FAs finished servicing PAX. The upset stomach became more painful cramping and I began getting nauseous. I told the Captain I couldn't wait any longer and needed a break ASAP. I got up out of the seat to wait for FAs to setup break and felt very lightheaded; nauseous; was sweating; got tunnel vision; and ultimately fainted behind the pilots' seats. I woke up within 5-6 seconds; declared that I was okay. Opened the flight deck door and prior to entering the lavatory fainted twice while being assisted by FA. I again was up after a few seconds still with severe stomach pain so entered the restroom to attempt to relieve myself. I wiped my forehead with a cold towel and asked FA for some water. The crew were able to find a neurologist to assist. I exited the lavatory and the Doc asked me several questions such as my name; where we were coming from; where we are going to; type of place; DOB; etc. Additionally he checked my vitals which were normal. I told him what happened and he was 100% sure it was not a seizure; and believed that the food poisoning caused the severe stomach cramps; which in turn caused my pulse and blood pressure to fall below a certain point to cause a vasovagal response. [The] Dr. also noted due to me being physically fit and a runner my resting heart rate; blood pressure; and pulse is very low and it is very common for athletes to have vasovagal responses due to this. My stomach was still a upset so I went back into the lavatory to force all of the Protein Pack out of my stomach. After that; I felt 100% and went back outside and chatted with the Dr and FAs then returned to the flight deck. [A F/A] had been in the flight deck with another F/A while I was being looked at. We were already descending in the mid 20s towards [a divert airport] by time I got back into the seat. A deadheading [pilot] identified himself to the crew and joined us in the flight deck. The Captain and I discussed a plan for the arrival. Since there was still a lot of coordination to be had we both felt comfortable with me flying and him finishing up all of the coordination and checklist. Flew the ILS 34L for a uneventful landing. Once at the gate; I exited the aircraft and met with EMT personnel. They checked my vitals; blood sugar; as well as checked my heart and everything checked out normal. I explained what happened; and they agreed that the condition was a vasovagal response caused from cramping due to possible food poisoning and that I was fine.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.