By eating the majority of your calories / carbs post heavy barbell training (and with a surplus for the day) you are telling your body to partition those nutrients to repair muscle & grow for the next training session. The effect of this CNS stimulation occurs for several hours and into the night.
Now on your "rest" days, by slightly undereating and limiting carbs (not like a 1000 calories under) and still being in that "repair" mode, your body will take the calories you provide it and prioritize muscle building. By that same prioritization, it will utilize your body fat stores to make up the deficit.
Over the same time window, 6 months for instance, you would likely see similar changes in body composition when compared with a standard bulk / cut. I would argue by efficiently making use of nutrient partitioning you will slightly stronger/leaner as well. Especially if you were sub 15% body fat when you started, since there are significant hormonal advantages at that level of leanness (regarding fat gain/loss while bulking).