In the ongoing discussion of whether being over or underfat increases or decreases one’s mortality, people often miss a key point: activity level, rather than body composition per se, is often the most important factor.
Although weight/level of bodyfat has important chemical and mechanical effects on its own, in mortality data it’s often just a proxy for nutritional quality, fitness, and activity level. On average, higher % of bodyfat (past a healthy range) correlates with lower activity levels and poorer quality nutritional intake. (Yes, there are exceptions. But they’re exceptions. Please, find me a Navy SEAL with 35% bodyfat.)
Speaking at APA’s 117th Annual Convention, Steven Blair, PED, called Americans’ physical inactivity “the biggest public health problem of the 21st century.” I personally think that the shit pooped out by the industrial food system is the biggest public health problem, because at least if you’re not as active you wouldn’t be exposed to processed garbage, but whatever — really whether you focus on low activity levels, nutritional napalm, social geography of a car-based society… it’s just rearranging deck chairs on the Titanic.
We know that only a small minority of people in North America are regularly physically active. Research has shown approximately 25 percent to 35 percent of American adults are inactive, Blair said, meaning that they have sedentary jobs, no regular physical activity program and are generally inactive around the house or yard. Never mind “doesn’t get much exercise” or “walks for 15 min 3x weekly”. That’s COMPLETELY PHYSICALLY INACTIVE. As in basically lying there like dead fish nearly 100% of the time.
Blair’s data comes largely (pardon the pun) from the Aerobics Center Longitudinal Study, which suggests that fitness level was a significant predictor of mortality — one follow-up study of 40,842 people suggests that poor fitness level alone was responsible for 16% of all premature deaths in both men and women. The ongoing study began in 1970 and includes more than 80,000 patients.