There's no magic macro ratio for weight loss. You need to create a slight calorie deficit in order to lose weight but lifestyle factors also play a roll. It's not quite as simple as calories in vs. calories out. To set yourself up for success, while you could eat junk food and still lose weight, I would recommend focusing on getting protein at every meal, getting your carbohydrates from low-GI, unrefined carbohydrates and eating some healthy fats. For most people that looks like 50% of your calories coming from carbohydrates, with approximately 25% coming from fats and 25% coming from protein. From there you can adjust that ratio depending on what works for you while staying within an appropriate amount of calories for your goals.