I can't agree enough with the HIIT being extremely taxing.
I used to do it 4 times a week and weight lift the other 3 days, this was during what I call the dark ages because I didn't know anything.
It was a fat loss phase which actually turned out to be an extremely effective muscle loss phase.
Needless to say I haven't done HIIT in the two years since, if I was to do so I would do it maybe once or twice a week. These days I'm usually only jogging for about 10-15minutes once - twice a week. It depends on how much I am actually training in the gym.
Right now that works out to be 6 sessions in the gym a week push/pull/legs, AM and PM workouts one for strength and one for hypertrophy. For a relative beginner/low intermediate like myself it works extremely well as a form of cardio as well as a general lifting program.
I've tried splits, total body workouts and none of them quite work like two a days for getting lean whilst gaining muscle. (Granted a lot depends on diet as well)
-- Speaking of diet,
Currently I workout mon/tue/wed & fri/sat/sun I'm typically in the gym for 45 minutes each session, maybe slightly more on pull day as the back is my weakest area.
I'm gaining weight and losing size on my waist, I'm taking photos and size measurements every two weeks. Things are going well.
Overtraining isn't going to happen to someone at my level even with this amount of lifting as long as diet is fine.
Typically my diet is as follows on workout days.
Wake: Oats, 1 pint of Milk, 1 bowl of Vanilla Yoghurt - if I can stomach it I have a bacon and egg toasted sandwich too.
Snack: Super shake - 3 eggs, 1 banana, 1 pint of milk, 1 tbsp jam, half cup yoghurt 1 tsp l-glutamine powder blended up.
Lunch: tuna + mayo bagels and 1 pint of milk
Snack: 3 boiled eggs + 2 Flameout pint of milk
dinner: Whatever is cooked for everyone in the house, burgers = 3 half pound burgers, pizza = a whole pizza, so on. and a pint of milk
Snack: super shake
Snack: Another bagel and a pint of milk!
before bed: two Flameout, yes more MILK!
It seems to be working right now, once I reach 200lbs I'm going to be eating a lot more chicken, veggies and stuff like that and cut down on the milk. But its cheap and keeps me going right now during the training sessions I'm doing.
On a non training day I cut out a few of the later in the day snacks and drink less milk...
Keeps carbs and fats lower, protein drops off a bit too but I'm getting some whey protein soon so that'll be in check.