Originally Posted by
Rosie Chee 
If you're going to add in HIIT, I recommend three days a week with a day between sessions (i.e. Monday/Wednesday/Friday or Tuesday/Thursday/Saturday), on days alternate to resistance training days if you can (since it elicits the same kind of response as resistance training without the stress on your CNS).
If you're dieting and you SIMULTANEOUSLY LOWER your calories even MORE and ADD in more training, then you're highly UNlikely to GAIN overall body mass.
If you want to GAIN weight, then you need to either be a) recomping, using calorie cycling for lean mass gains (although this said, you could be slowly gaining muscle mass but losing bodyfat, so seeing no or little change, and sometimes DEcrease in overall body mass); or b) eating MORE than Maintenance and focusing solely on muscle gains.
Also be aware that SCALE weight is IRrelevent (and you admit you need to stop looking at the scale every day) - if you look at your weight daily, remember that it constantly fluctuates, not just over the week, but throughout the DAY, and to "measure progress", use only the measurement taken on the same day each week, ideally seven days apart (i.e. every Saturday or Sunday, etc.). It's your BODY COMPOSITION that's important, since you can be losing bodyfat, but gaining muscle mass and seeing little or no change in scale weight, etc.
If you simply want to gain overall body mass (i.e. weight), that's easy enough and you can do that through your nutrition, manipulating carbohydrate, water, and sodium intake - whilst it may be "lean body mass", it is NOT muscle mass gained though, so keep this is mind.
~Rosie~
