I love Primal Blueprint, its nutritional advice is amazing and I'm seeing pounds flying away effortlessly ever since I shied away from grains in favor of saturated fat and the like.

However, I am really skeptical about the fitness advice offered in PBF. How on earth can 1x/week sprinting and 2x/week strength training make you ripped? Especially when the sprints are 10-20 mins and the strength training is 10-30 mins. That amounts to 30 mins - 2 hours of high intensity training per week. What scientific evidence is there to support this is at all an optimal way to train? I understand the risk of over-training and burnout, but this seems to take things to the other end of the spectrum, ie undertraining. Would you really be worse off strength training 3-4x/week and sprinting in the days in between?

I don't see how this makes sense from the hypothetical Grok's perspective either. Why would Grok only need to sprint once every 7-10 days? Surely he must dash away from predators more often than that. The same skepticism applies to lifting heavy things. Wouldn't there be days where Grok would have to hoist heavy things over his shoulder for an entire day? And in general, the need to lift heavy things would be far more sporadic than a dedicated 10-30 min workout. All to say, thinking fitness in terms of Grok is highly speculative, so you really need scientific backing for these LHT & sprint workouts. Unfortunately most of the citations in PBF are links to Mark's own articles.

I agree with the concept of having 5-6 essential movements and that chronic cardio is harmful in a variety of ways, but I can't shake the sense that PBF needs more workout volume to achieve any kind of results. Is there any particular reason that a "conventional wisdom" type program like Starting Strength would be wasting your time?