What is your take on daily exercise? If I lift a 5×5 three a week, is it okay to spin on the in between days, or should I let my muscles recover?
Also, do you eat a peak meal on days that you don’t exercise?
As I mention in the book, I think it’s great. The more the merrier. I might debate the merits of Spin class, but as long as the intensity is high enough there’s nothing wrong with using it as an interval exercise.
One thing I would recommend (and I do recommend in the book) is that you allow for proper recovery, which includes both adequate sleep and active recovery, such as taking a decently long walk. Honestly, if you had the time on your hands, there’s nothing wrong with weight training every day and doing interval, provided you get proper recovery. If you find yourself fatigued or with reduced performance, you simply either increase active recovery (more massage, more rest, more walking and so on) or scale back training. It’s pretty straight-forward.
It’s not like in ye olden times (of a whole century ago) dudes would be like “hell, guess I can’t toil in the fields since I just chopped wood. I’ll overtrain! MWF is butter churning, T-Th is for wrangling livestock. Better eat mah glucose snakes.” What a horribly hamfisted analogy, but hopefully the gist is clear.
As for Peak meals, no. I don’t recommend them if they don’t accompany an appropriately intense activity. I sometimes take a Sunday off as a complete rest/recovery day, and those days basically mirror a meal plan from a ketogenic low carb diet.