Macronutrients are secondary to cutting calories. Once you get enough protein to maintain or build muscle and enough fat to fit dietary requirements you can eat as many carbs as you want so long as your calories come in lower than what you burn.

That said, many people find it easier to control their food intake by eliminating simple carbs. Swings in blood sugar can create cravings and eliminating or reducing carbs will reducing or eliminate such cravings.