This is not true, the day you eat the 3000 kcal your body will have the potential of burning way more through thermogenics than before, considering you were in a deficit. You will probably feel stronger the day after your higher kcal day, and a lot of the kcal will be used for muscle glycogen if you train hard and are in a deficit the other days.
The excess amount of kcal you get during the cheats can only help you to an extent though, lets say you eat 5k kcal one day, compared to if you had 20k kcal, there wont be a really big difference in thermogenics and so on. Hope this makes sense.
Also, drink a lot of water and get your daily vitamins in, and don't miss out on fats and fibers. One can go on a diet, cutting away too much fat, leading to hormonal surpression and potential to burning fat. I've heard one guy losing his testosterone production because of being on a very low fat diet. I myself am going for at least 50-60g of fats per day. Eggs, nuts, fish, are great options. Oatmeal provide a stable energy source with very good micronutrients. I try not to go crazy on my breakfast as this for me causes lethargy. A few hundred kcal for breakfast, getting in a fair amount of healthy fats, good carbs and some protein. Try get a smaller, carb-meal before your workout (with a lot of water drinking in between your breakfast, your pre-workout meal, and the meals in between if any.) The water drinking combined with this carb-source provides with good fuel during the workout, and a very satisfying pump!
Always try having calories left for before bed, without having to "starve" until this final meal. So don't save too many, but save a few hundred kcal for before going to sleep. Try getting in slow proteins, which will help you feel more fed during the mornings, and not wake up with cravings during night. And always start the day of by fueling the body with water, and don't wait too long before getting the breakfast in, so you don't get too much of an appetite.
And if you drink coffe, or take any fat burning supplement, I would suggest waiting a couple of hours before drinking it after waking up, not instantly. When we wake up, our body starts a natural process getting us up and going. Feeling more energized during lunch or dinner compared to just when you wake up in the mornings? That's because of our bodies ways of getting us up and going. If we drink coffe for instance during this process, we won't get the full benefit of neither the coffe or the way our bodies naturally handles it. I hope this makes sense. Everything is about longgevity, so take things step by step, make all the things build up into a lifestyle. Don't see this cut as work or tough times. This will just lead to nothing lasting when you finish this race. Try making this 100m sprint, a beginning to a marathon!
