Calories are the basic unit of energy found in all foods and are necessary to maintain the body's vital functions or basal metabolic rate. The amount of calories a person needs depends on factors like their age, gender, and lean muscle mass.
Eating too few calories for a prolonged period of time causes a person to become underweight (per the BMI) leading to muscle atrophy, weakened immunity, and eventually, organ failure. Conversely, eating too many calories causes a person to become overweight and obese, increasing their chances of heart disease, type II diabetes, and cancer.
People looking to gain weight in the form of lean muscle mass can aim to eat around 3000 calories per day depending on how many strength building exercises they are doing.
Healthy high-calorie foods include granola, meats, tofu, fish, avocados, milk, beans, sweet potatoes, whole grains, and nuts. In general, the daily value (%DV) for calories is 2000 calories per day, but people active with strength training or other exercises may want to consume more.
Below is a list of the top 10 high calorie foods ranked by common serving size, if you are looking to lose weight, see the list on unhealthy high calorie foods to avoid. If you are looking to gain weight, see the section on select meal portions for eating more calories, and the article on high calorie weight gain meal plans.