What exactly is a high protein diet?

>30%: High in proteins such as beans, nuts, meats and dairy. A chicken breast has about 20 grams of protein just to give you an idea. Normally you want around 30 percent of your calories to be from protein so anything higher would be "high protein".

Bulk of calories: Comes from eating mostly protein. At minimum you should eat 1-2 gram protein per kg of body weight while limiting your carbohydrate and fat based calories.