Thanks Roush - My goal is to add muscle mass.
What about macros? On a cut I kept carbs low / moderate (100-125g) on workout days and very low (30-35g) on rest days (typical 5 on 2 off). This was very effective in dropping BF. Is it OK to keep carbs in this range and up my protein / fat (to a lesser degree) in order to add calories (going from maintenance to surplus). Is really upping your carbs beyond 100-125g necessary to add muscle mass?.
if your carb sensitive and your wanting to keep BF% in check , then you probably do need to keep carbs on the lower end.
but, I will say that for a 'massing cycle' carbs are pretty important . they are anabolic and anti-catabolic (not anabolic in the way that protein is , being muscle growth needs the amino acids/protein for building muscle) .
Carbs provide an anti-catablic because when there is plenty of blood glucose and glycogen stores your body will use that for its preferred energy source,, on low carbs and depleted glycogen stores your body can use protein (via Gluconeogenesis) as its energy source as well as breaking down its own muscle 'catabolism' for energy .. so not only are you loosing out on protein as the raw material for muscle growth , your loosing muscle itself as well.
again, with plenty of carbs in your system , then there is no need for the body to do this.
Carbs are 'anabolic' in that they help drive nutrients (glucose becomes glycogen stores in the muslce) and especially water into the muscle cells. This is beneficial for both strength and muscle growth , as well as muscular endurance ,, which plays a role in hypertrophy as well being training beyond perceived failure will generate a lactic acid response (and studies have shown lactic acid as a factor in muscle growth)..
training with low carbs will deplete glycogen stores rapidly .. and not refueling those glycogen stores adequately will negatively effect hypertrophy.
so I'd say that upping carbs for a massing cycle will definitely be beneficial to the goal of adding muscle mass.. however being carb sensitive means you'll have to pay careful attention and adjust often.
along with carb cycling , you may benefit from carb 'timing' as well . getting most of your daily intake of carbs in the hour windows before and after your workout (but no carbs at other times, example in the morning no carbs , if your workout is in the afternoon).. this way you can still take in higher amounts of carbs , but timing can help you use those carbs more effectively and possibly help out the carb sensitivity .
note: I've tried to bulk on a ketogenic diet .. it was a failure . I've bulked on high carbs with way way more success. . i'd rather add just a bit of fat knowing the mass gains are there too .
because , it is way easier to loose body fat , then it is to build muscle. being the latter is much harder , you should commit more efforts to the massing phase then the cutting phase imo.