You are experiencing what Dr. John Berardi deemed as “g-flux”
Put simply: there’s more to food than just calories. Assuming you are picking good food choices, you are providing your body with many awesome nutrients (vitamins, minerals, fatty acids like Omega 3s, saturated fats and cholesterol to promote testosterone production, carbs that can reduce cortisol, etc).
If we just do blanket caloric restriction and aren’t strategic in our approach, we simply consume less of all these good things.
If we ramp up activity, we can consume more calories in total and, with that, more food, and with THAT, more nutrients, while still having the same net caloric balance compared to if we ate less food with less activity.