> I remember Kevin Smith talking about his first stab at dieting, following the instructions of the "guru" that got Penn Jillette lean

Penn's a very good writer and hacker (this is a temporary diet hack, after all), and if you're interested you can read more about this here: Presto!: How I Made Over 100 Pounds Disappear and Other Magical Tales: https://www.amazon.com/Presto-Pounds-Disappear-Other-Magical...

Penn credits Ray Cronise for literally saving his life. You can read his 2014 paper The "Metabolic Winter" Hypothesis: A Cause of the Current Epidemics of Obesity and Cardiometabolic Disease, here: https://www.liebertpub.com/doi/pdf/10.1089/met.2014.0027