One of the things people say caught them most off guard once treatment started was their appetite. Even a food they used to love can suddenly turn the stomach the moment it is in front of them, and some say that putting it in their mouth feels like chewing sand. When lung treatment overlaps with chemotherapy or radiation, taste can go dull or the mouth can get sore, making eating even harder. You do not eat, so you have no energy; with no energy, nothing appeals to you even more. That vicious cycle is the scariest part.
So for the first few days, it helps to let go of any ambition. If you set out three full meals like a cafeteria tray, just looking at it is enough to put you off, so going with small portions a little at a time, often, is more realistic. Aim to get even one bite down every two or three hours. People say porridge or thin rice gruel feels easy on the stomach, but the truth is that eating only porridge leaves you far short on protein. If you beat an egg into it, or add softly cooked tofu, finely minced chicken, or white fish, the same bowl carries a whole different substance.
If smell is the problem, try lukewarm or slightly cold food rather than something hot. The smell that spreads with the rising steam often triggers nausea, so chilled steamed egg, soy milk, yogurt, or a spoonable pudding can go down surprisingly well. When your mouth feels rough and pasty, a sour taste can help; rinsing your mouth with lemon water before a meal, or adding a little tartness to the food, gets the saliva going and makes eating a bit easier. That said, when your mouth is sore, sour, spicy, or very salty things can sting and irritate instead, so it is best to adjust to how you feel that day.
There will certainly be days when nothing goes down at all. On those days, getting your calories by drinking rather than chewing is the better route. Think of things that pack nutrition into a single sip, like a shake blended from milk, banana, and soy milk, roasted grain powder drink, or a protein supplement drink. If you drink a lot of water right before a meal, you fill up fast and end up unable to eat the food, so the trick is to spread your fluids out between meals. And everyone has a time of day when their appetite comes back, even briefly. Many find mornings the most bearable, so do not miss that golden window; keep on hand the food you eat best at that time.
If you lose a noticeable amount of weight within a week or two, if swallowing gets so uncomfortable that even a sip of water is hard, or if the vomiting will not stop, do not tough it out alone; be sure to tell your care team. Many people assume a lost appetite is just something to endure, but these days there are ways to help your appetite or ease nausea, and you can also get separate nutrition counseling. There is a reason people say eating well is part of the treatment too.
This piece is simply shared experience with others going through a similar time, and any actual changes to your diet should be decided in consultation with your own medical team and dietitian.