i think i may be more concerned about the conditions you are staying in when you are in KL rather than the flight. I mean, making sure you know what you are eating, that it is prepared safely, drinking water is safe, hygeine standards of your accommodation, and activities you will be doing. For example, i imagine it wouldn't be a great idea to go trekking through moutains, staying in local villages and eating food that you don't know what it is. Unless you are a local, your body may not be used to these conditions.