The terms 'caloric surplus' and 'caloric deficit' refer to the balance of calories consumed versus calories expended. A caloric surplus occurs when individuals consume more calories than they burn, leading to weight gain. This is often sought after for muscle gain. Conversely, a caloric deficit happens when caloric intake is less than caloric expenditure. This leads to weight loss, which is commonly pursued for fat reduction. Both concepts are crucial for understanding weight management in the context of fitness and nutrition.