Girls who want to gain weight quickly must take a calculated method to raise their caloric intake and encourage a healthy weight growth. Consume calorie-dense foods like avocados, nuts, seeds, whole grains, lean meats, fish, eggs, dairy products, and legumes that are high in healthy fats, proteins, and carbohydrates. To increase calorie consumption, concentrate on eating more frequently and in greater portions throughout the day. To increase muscular mass, including resistance training and weightlifting activities in your strength training regimen. Steer clear of intense cardio workouts that could burn too many calories. Make sure you're getting enough sleep and water as well to promote general health and muscle recovery.