Rice and chicken lol. If you want to avoid getting a ton of fat i recommend working out. There are probably tons of options but i know of two: calisthenics and weight lifting. Calisthenics is using body weight instead of like dumbbells. I would try both and choose which one you like most since it can affect how well you stick to it BUT either way it's going to be hard. It's gonna hurt, it's going to take time, you're going to fail at times, and it's going to take some money. If you also want to be athletic or just like flipping around like an idiot I recommend calisthenics, you basically train like a ninja, or like the guy that plays green arrow from the CW. Anyway if you want to gain weight you need a good diet. Some people just eat like 20 Mcdoubles a day ( exaggeration please don't do this) and get muscle but also gain a lot of fat, then they lose weight it can be cheaper theoretically but it takes longer and is kinda dumb so i would recommend doing it the slow and slightly more expensive way: eating actual food lol. Atm i eat like 2-3 eggs in the morning with 2 servings of oatmeal, for lunch ramen noodles cuz they're cheap, then i drink a protein shake with whey protien powder and peanut butter, milk, some vitamin powder and hopefully yogurt and a banana. For dinner rice and chicken maybe broccoli too. I suggest a meal plan because it's easier to keep up rather then winging it constantly but you should still mix it up every now and then. Also try to get around the 1 gram of protein per pound, no more is needed it's useless at that point. Make sure you get enough calories too, you can use the internet to calculate how much you need. Get a solid workout plan with minimal cardio if any, make sure you work put each area of your body unless you want hulks arms with toothpicks for legs. You can also look up work out plans on YouTube. Always try to progress in some way so you never get used to what you're doing and push yourself. The most important part is probably consistency though, you need to do this for a long time, you're looking at probably a minimum of six months. If you stop or skip workouts you'll ruin your gains and waste time. You should only need to workout 3 times a week, i do on Monday, Wednesday, and Friday and the last two i can do whatever. Expect to be sore, but honestly for skinny people the hardest part tends to be eating believe it or not. Most skinny people don't get enough calories and or protein so they don't gain weight, since you're used to not eating enough it can be hard to constantly eat when sometimes you won't want to. The protein shakes are supposed to make you feel full or something so i struggled with those a lot at first. Also since you will be eating more you should watch junk food, for me i ate candy ( sweets are bae) a lot but now that i eat enough for my body, adding 500 calories from sugar or fat is not good at all. In theory you could end up just getting fatter. Luckily i work enough so that i can still be fat and fit at the same time hehe. Anyway hope this helps. You can gain a maximum of half a pound a week, supposedly, so it will take time. I think skinny guys are the exception because i gained like 3 pounds my first week, that could be from muscle memory or just because something else but idk. I don't gain that much regularly though my gains have been much less since then but some people have said skinny guys can gain more weight because they are so skinny, we'll just say they have untapped potential because I'm not sure how that works.