Yes, you can also follow a keto diet to gain weight or maintain it. If you follow keto to gain weight, you should ensure you take in enough food. This can be hard because the normal tendency of keto diet is to cut down your appetite so make sure you count your calories. Take in liquid calories and have food like butter to consume the proper amount of calories. If your focus is on gaining muscle, you should take in more proteins than the normal diet. In case you are unable to keep weight with this diet, it’s advisable to switch to moderate-carb diet, Paleo diet to get better results.