Do you believe one should try to get "fat adapted" by low carbing for a few weeks before doing something like this? Also, isn't this somewhat similar to a once or twice weekly carb up meal?Carbohydrate is not directly stored as body fat, and de novo lipogenesis - the body converting carbohydrate into fat for storage - is a very inefficient mechanism. In order for the body to store carbohydrate as fat:
1.) First glycogen stores must be completely full, which is almost never (unless you're going to eat immediately after eating).
2.) Next, glycogen stores swell and overcompensate. During overfeeding, especially in people that lift, glycogen stores can swell up to 100% normal capacity to overcompensate for spillover.
3.) After that, overfeeding of carbohydrate causes the metabolic rate to increase significantly. So now you have to overeat past the metabolic rate increase.
4.) Then your body has to go through the effort of converting carbs into fat to be stored.
Dietary fat, generally, is immediately stored as fat.
When you eat carbs and fat in unison, it is the dietary fat being stored. If you eat very low carbohydrate, generally the increased stress hormones required for converting lean tissue into glucose has an appetite-supressive effect, so it's easier to maintain a deficit. Unfortunately, this promotes lean tissue loss and fat preservation. It is more effective to eat higher carbohydrate in a deficit to preserve lean tissue because carbohydrate is significantly more anabolic than fat and cortisol is suppressed when carbohydrate is consumed. The lower your intake of carbohydrate, the higher your average cortisol is (since cortisol is the primary hormone used to break down animo acids into glucose via gluconeogenesis) and the greater your insulin resistance is.
What does this all mean? If I were in your case, I would:
1.) Consume a higher carbohydrate/lower fat diet in general.
2.) On days you work out, try and eat very low fat (<30g a day) with much higher carbohydrate - at least 40% of your total calories. Try and eat a small caloric surplus on these days.
3.) On days you don't work out and just do cardio or are sedentary, drop your carbs, but don't take fat intake above moderate. Something more like 30-35% calories from fat. Protein intake should be constant, but since you're taking in less total calories on this day it'll be a greater percentage of total calories.
Salt your food well to maintain thyroid function, especially on deficit days. And as always, try your best to make the fat you do consume saturated fat with low polyunsaturated fat.
This is what I do.