It has to do with the duration of time spent being sedentary.
They say a picture is worth a thousand words, but luckily enough today you get both.
Sarcopenia: “poverty of flesh,” or the age-induced loss of skeletal muscle mass, strength, and function = reduced quality of life. Sorry old-timers, but I hereby officially revise the definition from “aging-induced” to “sedentary-induced.” Herein, I present evidence that sarcopenia is not a phenomenon of aging per se, but rather of disuse atrophy. Dear Webster’s & Britannica, please revise accordingly.
Skeletal muscles: use ‘em or lose ‘em #TPMC
Thanks to Julianne Taylor & Skyler Tanner for directing me to these images.
divide and conquer
Exhibit A. Chronic exercise preserves lean muscle mass in masters athletes (Wroblewski et al., 2011)
This study evaluated “high-level recreational athletes.” “Masters” just means they were over 40. And “high-level” doesn’t mean “elite,” it just means they exercised 4-5 times per week. These weren’t super-obsessed gym rats… it’s probably who I’ll be in 7 years [sigh].
= pharmaceutically enhanced low fat diet. 
makes some of the strongest athletes in the world because unlike most other training regimes, they are constantly lifting very heavy weight. Other protocols restrict heavy lifting to certain times of the year, in-season / off-season, etc. At Westside, you’re going heavy on an exercise that changes very frequently (every 1 – 3 weeks). And it’s this latter point that provides the basis for why other people think Westside works. By constantly changing which exercise is lifted at maximal intensity, the body never fully adapts, or gets into a rut – this is part of Westside’s ‘Conjugate Method.’
, as per their 
theory: small doses of individual exercises, eg, conventional deadlifts one week, good mornings the next, sumo deads the next week, and so on and so forth – will improve your squats; the body never knows what’s coming (even though you might have planned it weeks in advance, or at least planned to check 
, wherein being prepared for “random” shocks seem to benefit the system as a whole, or make it stronger. Sedentary makes you fragile, weak, and soft; exercise makes you robust; Westside is Antifragile.
CS (+ some other chemicals). But those kids didn’t do that. they ate less of other foods.
that warrants attention. (it could be the increasing fat intake, but for now let’s just say it’s RYGB per se). According to this pearl, weight loss of only 10% via diet alone causes energy expenditure crash by 394-500 kcal/d, and physiological replacement of leptin via subcutaneous injection can increase this by 234-454 kcal/d (