The first point is very important for avoiding altitude sickness and your guides will likely keep reminding you.
Drink, Drink, Drink! Water is your best friend at altitude! Keeping yourself hydrated at altitude is extremely important. Your body dehydrates much quicker at altitude. Therefore, you need to replenish your fluids and drink a lot more water than you may do back home. We recommend drinking anywhere from 4 to 5 liters a day when at altitude. If you follow this rule, you will eliminate altitude sickness and keep yourself feeling good throughout the trip!
Eat Plenty: For many people, it can be very difficult to eat at an altitude. Even with all of the physical energy you are exerting, for some reason, food does not always sound good when you are at altitude. The main thing to remember regarding this is that you are burning a TON of calories while trekking on Kilimanjaro and your body needs to replenish these calories if you want the best possible chance of summiting. Don’t let this scare you into thinking that you will not have enough food to eat on the mountain” this is far from reality. You will be overwhelmed by the plethora of food on offer every meal, everything from pancakes to soup to maybe a special treat of chicken wings! There is always plenty of food to choose from on the mountain, but when your tummy is having a hard time with the altitude, those familiar snacks may be all you can get down.
Keep Warm! The correct gear is a MUST on altitude, just because shivering isn’t nice and hypothermia is dangerous, and staying nice and toasty will lessen your risk of succumbing to altitude sickness.
Keep your daypack light. Only take what you really need. Every extra kilo needs extra oxygen to carry.