High-level athletes are often the most disciplined people you'll meet.
6 hours of training 6 days a week isn't an uncommon thing, and it's often accompanied by a 'laser focus' style of strict nutrition.
Because the energy requirements of such high amounts of training are so great. You'll need to eat a lot of Calories and a lot of carbs to avoid states of low energy availability relative to requirements in order to perform your best and not impact your health.
So what are these requirements, how much carbs do you actually need to eat if you train multiple hard hours day?
5-8g of carbs per kilo of body weight per day. [1]
For a 75kg athlete, the range is 375g- 600g of carbs a day
Once you know what 600g of carbs looks like in terms of physical food. You'll realise that achieving such high requirements through exclusively 'clean foods' isn't viable.
To consume 600g of carbs you'll need to eat...
6.2 kilos (raw weight) of sweet potato. [3]
Or
1.2 kilos of (raw weight) rolled oats. [3]
... I think it's safe to say that's not really viable on a consistent daily basis.
So if you're training 6 hours a day and eating only 'clean carbs' to hunger satisfaction or even fullness. It's logically doubtful you're getting even a small portion of your carbohydrate requirements on a regular basis. You're likely in a state of chronic low energy availability which can have massive implications. This state and it's negative outcomes is termed RED-S (relative energy deficiency in sport) [2]
Health consequences of RED-S include bone, metabolic, endocrine, menstrual, cardiovascular, immune health and more.
Performance consequences of RED-S include injury risk, impaired judgment, cognition, strength endurance performance and more.
The magnitude of the above consequences can be utterly shocking.
So if you want to perform your best and not negatively impact your health you might want to eat some 'junky' carbohydrate dense foods. There are many ways to easily consume high amounts of carbs. Typically calorie dense, super tasty, low fibre foods are great.
For example, 680g of Coco Pops will give you 600g of carbs.
While still a massive amount. It's far less than the aforementioned 'clean carbs', and you need to consider taste, and the fibre content to get a better idea of actual ease of consumption comparisons.
So if all of the above is relevant to you. You might want to consider;
Swapping the oats for white rice, and putting honey and jam on top of that. Drinking fruit juice and full-calorie cordial with your meals. Swapping the whole grain bread for bagels with jam, and maybe having a full tub of sorbet for dessert.
Thinking you 'need to eat only clean' might not only be causing you to perform sub-optimally but it might be seriously harmful to your health.
Want to learn more about how to improve your performance in training?
[1] https://jissn.biomedcentral.com/articles/10.1186/s12970-018-0242-y
[2] https://bjsm.bmj.com/content/52/11/687
[3] http://www.foodstandards.gov.au/science/monitoringnutrients/afcd/Pages/foodsearch.aspx