"Calorie excess" refers to consuming more calories than your body needs to function properly. It happens when you eat too much food or when the food you eat is high in calories. This can lead to weight gain and other health problems. Full definition
Remember, you need a slight calorie excess to build muscle. (cathe.com)
A 100 calorie excess per day translates to a 10 pound weight gain in that same year. (personal-nutrition-guide.com)
Even overshooting slightly at each meal can add up to a hefty calorie excess over weeks or months — and it's easier to skip half a spud than try to claw back a couple of kilos. (womenshealthandfitness.com.au)