I'm eating to gain muscle mass. It's working. I was ZC for a while to get fat adapted and heal my metabolism, then Leangins cut with ZC rest/carb post workout, both with great success. I intermittent fast everyday 16/8 eat at noon and night.
This winter I've been lifting heavier, done zero cardio, and eating for three. I've gained a lot of muscle. I've been eating carbs every day, once, in the evenings all days, aka CBL, unless my workout is earlier in which case I always take them immediately afterwards.
I eat carbs alone. Let em digest. If not eating carbs I eat meat and fat. If taking meat close to carbs, I eat it lean with no added fat.
When I eat carbs after working out, I'm good as gold. Feels great. No issues.
When I eat carbs later in the evening after a midday workout, I'm still pretty good.
When I eat carbs on a rest day, I wake up at middle of the night low blood sugar and hungry. Then when I wake up, my hormonal hunger is terrible for hours.
This problem doesn't change with: Carb type Glycemic type Load Calories Timing
As long as I eat carbs on a rest day, it happens! If I eat a few carbs, it's worse than a lot. Doesn't matter if I eat meat and fat or lean meat with them. Nothing seems to matter, except that its a rest day.
Now, I can hear you saying, "stop eating carbs on rest days"
Not so simple. I NEED CALORIES to grow! I am gaining. It's working. Even if I eat 800g lean red meat (beef leg)daily and 100g added coconut oil / tallow / fish oil, that's still only 1800 calorie, not enough.
TDEE for me now is @2000-2200. Maybe a tad less on rest days. I must eat well over this to grow. Having MORE fat, over maintenance or TDEE is more likely to add bodyfat than build lean mass in my experience. Carbs build muscle in calorie surplus, no contest. And, they give a hormonal benefit to growth that excess fat doesn't.
So getting my 2-3000 calories on rest days with fat and protein is out. And I can't seem to tolerate carbs on rest days.
So what to do?
Whisper, recently added 50g carbs from taters to rest days, and changed fat to same amount all days. MCT with coffee am, MCT with lean beef lunch daily, remainder of cals and all long chain fats and carbs at dinners. Evening fat moderate and same all days, touch of carbs rest days, more pwo days. Presto, no more waking up hungry and sleeping like a baby!
Fat loss on a cut is working, it's all about calories and sticking to leangains cycling. Fat with carbs on all days fluctuating carb levels. Working.
I think that in the last comment you answered to @ROB you may have your answer. 1kg of sweet potatoes seems a lot to me! I'm pretty much like you, carbs when I'm not active make me feel a little bit off, and trigger my hunger a lot. There's some insight that if you have been metabolically messed in the past you may lack some proper functioning beta-cells that regulate the insulin response, which may be involved in the issue. Why feeling OK on workout days then? Because exercise could get the carb cleaning instead via other ways. Not an expert on the field by any means but maybe you'd try to do you'r research on this so you may draw some useful conclusions.
For me, eating greens for luch and a few (maybe only 200 dry / 400 gr cooked in one sitting) and a salad for dinner works very well... it's neither super low carb nor high and very well tolerated. Having a post-workout whey shake and some BCAA and quality protein in every meal has helped maintain and even put some muscle mass in the past, now just maintaining as I'm an endurance runner and it's quite troublesome for muscle gains.
So what's the issue? Rest days are very easy on a paleo diet. LG-style diet calls for low carb on rest days, so just eat fatty meats, fish and nuts on rest days, it's not hard at all. It's very easy to get your cals in without carbs on a paleo diet.
Or are you going low fat on all days? That's probably not advisable, since it will wreak havoc with your hormones - you need fat (cholesterol) for testosterone, and you need T for muscle growth. Besides, fat on a deficit day will not be easily stored (become bodyfat). That's why I'm slightly below maintenance on rest days even on a bulk. That's the "clean" part of clean bulk.
My history is pretty much the same. Very recently I transitioned to a LG clean bulk (-5/+30%).
My TDEE is 2300, and I shoot for 2100-2200 cals on rest days. I get there with around 50g of carbs, essentially one piece of fruit. I could easily halve my carb intake by forgoing the piece of fruit.
Workout day calories are tough. I'm currently going around 50g of fats for 2700+ cals, and it's not easy even though I eat over half a kilo of sweet potatoes.
You don't need to be on calorie surplus every day, as it's the overall calories you consume on a weekly/monthly basis what counts. Many go for surplus cals on all days, but those are not "clean" bulks.
If you're a 'hardgainer' and don't think a 'clean bulk' is feasible than why not eat the carbs on the rest day but not on their own? The problem may be that you're not having anything acidic or fatty with them to blunt to absorbtion rate; perhaps you're insulin resistant or 'reactive hypoglycaemic' to some extent, and eating them alone on rest days is contributing to you having the symptoms you're getting...
If that doesn't work, would having high protein on some of the rest days be feasible/desirable I wonder? I know it isn't great to to that over time but maybe it's an option...