Yep. It’s as simple as this.
Cutting out or severely restricting junk carbs is the starting point for this. And that’s better for your long run health also.
By the way, sugar via gels or soda before a workout also count as junk carbs. Eat some good quality carbs several hours before your workout instead.
Get a food scale, and weigh and track everything you eat for a week or two using something like my fitness pal. This will help you determine when you are in calorie deficit. Also, this could be eye opening on how many calories you actually consume.