Calorie dense foods or liquids, e.g. protein meal replacement drinks, peanut butter, nuts, protein bars, cheese, chocolate (if you skip meals and/or don't have time to eat). Acid reflux can be a problem if you're eating too many high fat/high sugar foods and if you're drinking a lot of coffee or carbonated beverages to get you through the day. Too much coffee or stimulants can make you really volatile and on edge, it disrupts your nervous system and sleep patterns. Shop when you're hungry and buy whatever appeals to you, but stick to a budget and look at use-by dates. Avoid getting stuck in a food rut and eating the same thing all the time because you won't want to eat at all. Make an effort for yourself, even if you're eating alone and you don't want to cook and you feel like shit. It does make a difference, it's a mental thing. But it can feel like your heart is dragging along the floor and things are shit/'what's the point' no matter what you do. If you don't care about yourself, no one else will.