A healthy diet isn’t a temporary regime, it’s a permanent lifestyle change.
Just counting calories makes no sense since they’re not all the same. If you get around 40% of your calories from fat, 25% from protein, and 35% from low-gylcemic-index carbohydrates (whole grains, legumes, sweet potatoes, winter squash, but no flour, sugar, or potatoes), and every meal includes large helpings of vegetables, most people will lose weight without feeling like they’re dieting (unlike Atkins and other ultra-low-carb diets).