I would initially start off by having my “off” days with lower calories. It just makes sense that you are expending less energy and should be eating less calories. However, the body doesn’t necessarily work on a 24 hour clock like we would like it too and may be still expending extra calories on our “off” days for recovery ect…
Personally, I would start with a lowered calorie “off” day and see what happens. If I found it hard to make progress on the scale every month or in the gym I would maybe bump up my off day calories or maybe even just increase my training day calories. Questions like these are the ones with answers like: Trial and error is the best option. Tell your friend to try some stuff and figure it out. Nothing beats actually “knowing” what your body will do when you do a certain dietary approach through experimentation. This will always beat “knowing” what your body will do because you just read stuff off the internet.
I believe your a big proponent of Lyle McDonald. I’m interested in reading some of his stuff. Is there one ‘best book’ you’d recommend as oppossed to having to track down multiple titles?
Depends on whether you’re looking to bulk up or cut down. I think the UD 2.0 has lots of great knowledge in it about hormones, glycogen depletion/replenishment, fat and carbohydrate metabolism ect. However, for some reason I like The Guide to Flexible Dieting. Its more of a guideline to how to adjust your dieting behaviors/implement refeeds. If you’re into ketogenic diets, then I recommend the Ketogenic Diet. I’m sorry I couldn’t be more specific, it really depends on what you’re looking for.