Contrarily, eating at a calorie surplus, is what causes us to gain weight. Funny enough, no one argues that eating too much causes us to gain weight. Yet, some “diet gurus” will try to mislead you into believing that calories don’t matter. That’s like saying energy doesn’t matter. It’s a completely absurd statement. When you’re eating at a calorie deficit, the body needs to meet it’s energy requirements one way or another.