Nothing ends a mountain trip faster than a stomach bug at 3,000 metres, far from a proper toilet. On the trail you cannot control everything, but most food and water illness comes from a handful of avoidable mistakes. A few simple habits keep you eating well and walking strong.
Water first
Unsafe water is the biggest risk. Treat all drinking water from streams, taps and wells in mountain regions unless you are certain it is safe; boiling, filtration and chemical treatment all work when used correctly. Be cautious with ice, which is just frozen local water, and with drinks topped up from jugs of unknown origin. Carry your treatment method at all times and use it consistently; most waterborne illness comes from the one glass you did not bother treating.
Hands and utensils
Your hands touch everything on the trail, then touch your food. Wash with soap whenever you can, and carry alcohol hand sanitiser for when you cannot; use it before every meal and after every toilet stop. Keep your eating utensils clean and personal: avoid sharing cups and spoons, rinse bowls with treated water, and let things dry fully rather than packing them damp. In teahouses and huts, a quick look at the kitchen’s general cleanliness tells you a lot.
Eat it hot, peel it yourself
Heat kills most pathogens, so favour freshly cooked, steaming-hot food over anything lukewarm or reheated. Be cautious with raw salads, unpeeled fruit and cold buffet dishes that have sat out, especially in warm weather. Peel fruit yourself, avoid undercooked meat and eggs, and be wary of unpasteurised dairy in remote areas. Street food can be excellent; choose busy stalls with high turnover and food cooked to order in front of you.
Storage and leftovers
On multi-day treks, store food securely from animals as well as from spoilage: hang it or use sealed containers away from sleeping areas, since rodents and larger visitors are adept thieves. In warm weather, eat perishable leftovers quickly or not at all, and keep snacks in sealed packaging rather than loose in pockets. If something smells or tastes off, discard it; on the trail, caution beats curiosity every time.
Safe eating in the mountains is mostly common sense applied consistently: treat your water, clean your hands, eat it hot. Do that, and your stomach will let you enjoy the walking.