Doctor's Orders: Plenty of Protein
I recommend you take in at least one gram of protein per pound of bodyweight each day, and even up to almost 2g per pound on workout days. Protein needs for individual trainees may vary, but this minimum ensures sufficient amounts with which to build muscle. If your bodyweight is low or if your caloric requirements for maintenance are high, then you may need even more protein than athletes of comparable size.
There is a lot of debate in the science community about whether consuming very high amounts of protein - around the 2 gram per pound mark - will result in more muscle growth. While most research suggests that you don't need more than 1 gram per pound, I still argue that those who train very intensely do need more protein.
None of the research on weight-trained subjects and protein intake involves the type of intense training that you find in a program like Shortcut to Size. When individuals who train at that level of intensity consume very high amounts of protein, they see great results as far as muscle growth and strength gains. I've seen it; my clients have seen it.
This is when I, as a scientist, step back from the lab and prefer to use recommendations based on everything I've seen in the gym. Eat your protein, kids!
Remember that every rest day should be an active rest day. Rest days are for recovery; they're not an excuse to be lazy. Get out and hit 15-30 minutes of HIIT cardio today, or perform 30-60 minutes of your favorite activity: hiking, biking, walking, playing a sport, etc.