It is important to seek urgent medical help (via NHS 111, urgent care, or A&E as appropriate) if you experience severe, persistent abdominal pain (especially if radiating to the back, which may indicate pancreatitis), jaundice/fever/right upper quadrant pain (possible gallbladder disease), inability to keep fluids down, minimal urine output, or signs of dehydration such as dark urine or dizziness
Weight loss and caloric restriction represent the most significant mechanism
For flights longer than six hours, consider peeking at your gel packs during the flight
doi:10.1900/RDS.2014.11.202 Gorgojo-Martnez JJ, Mezquita-Raya P, Carretero-Gmez J, et al
"Mechanisms, Pathophysiology, and Management of Obesity." N Engl J Med
For example, in the study by Novinscak et al