I know for sure you cannot out cardio poor eating. This is evidenced by every single person you see in the gym. They workout week in, week out...yet in all the years you've seen them in your gym they've made zero progress.
Why? Because the eat whatever they see. Doing 30 minutes of cardio won't undo that bottle of wine you had with dinner, or the basket of bread, or any of the other poor food choices. In order to make the kind of progress you need to make for significant weight loss, weight management, OR contest prep...you need to be in control.
When people wonder why you can't just have "one bite", this is why - every bite compounds. Nutrition is like interest in this way (saving money is another of my hobbies). One dollar isn't much of a big deal by itself. But when you leave it alone and let it compound over years...that baby will GROW!
One bite is a small thing, but every small bite adds up to something big. Your butt! Seriously, you have to keep your head straight around this. Everything matters. When I start prep, the first thing I do is cut out all the extra bites.
Last season, I lost 5 pounds just cutting out the "bites". Nothing significant. But in a week...5 pounds. Every bite matters in the big picture. So what if you find yourself in a weak moment? A dark, sad moment when you are about to make some serious damage to your progress by eating something off plan.
If you RECOGNIZE that moment, you've won. Now you make a choice. Your first line of defense is to always control your environment. Meaning, pack your meals and have them with you; shop what you CAN eat, not what you can't; and control your stress.
Cheating then requires planning. There's no accidental trip to the grocery store for a pint of ice cream. You didn't accidentally go through the drive through. You PLANNED to cheat. Which means you thought it out, and went to get your supplies, hid in your car/living room/garage etc. and you made a choice.
If you struggle in the evening, brush your teeth. Paint your nails. Do your house work. Lean to knit. Keep your hands busy. If you have food/snacks/treats in the house (for other people) put them on a special shelf in the cabinet - that is not your shelf.
Phone a friend. Call your coach. Ask for help BEFORE you pile that pizza in your mouth. There is no making up for what you're about to do. And every bite counts. If you think, "Oh, I'll make up for it later, tighten things up, eat more fish, do more cardio." you don't get it and it will show on stage. You won't be ready.
There is no "later", there is only right now. Having the personal strength to stay on track is hard. The world goes on all around you - there is no reason for it to stop. Your goals are different. Wanting to compete is something you have to REALLY, really want.
You can't just kind of like the idea of competing. You can't just want to prep during the week, or when it's easy. It's all the time. In order to make it to the stage, you must want it more than any of that stuff. You must want it deep in your core. You have to want it more than any bite.
And when you feel your resolve slip just the slightest bit, get connected with just how bad you want it. No one is asking this of you. You choose it. And only you can do it. Bite on that.