What is a high calorie diet?
A high calorie diet is the opposite of a low calorie diet, meaning you will consume more calories than your body uses.
If your body burns 2500Kcal daily and consumes 3000Kcal, you will be taking a hyper caloric approach.
The same example of a low calorie diet can be applied here, individual A spends 2000Kcal per day and individual B spends 3000Kcal per day, on a 2500Kcal diet, individual A will be following a high calorie diet and individual B a low calorie diet.
Hypercaloric diets are used to gain muscle mass/weight.