These issues are simpler to explain than the author realizes--and without any special invocation of Kant. Simply put, technology has made sex a lot safer at the same time as it has made food a lot more dangerous. Sex is safer (in the sense of creating fewer risks and uncertainties), as we all know, thanks to developments like condoms, STD testing, contraception, and legalized abortion. Meanwhile, food is a lot more dangerous, thanks to food science being used to create "hyperpalatable" junk food--cf. Paul Graham's "The Acceleration of Addictiveness."[1] As a 20-something in the U.S., I look around me and see obesity as an almost guaranteed outcome once people reach a certain age (with diabetes and heart disease not far behind)--and like many of my peers, I'm spooked.
In response to this, I wouldn't exactly say people have made healthy eating into a new Categorical Imperative. Instead, they've become paranoid and superstitious about what it is in modern food that's hurting them. Hence we get ridiculous cargo cults like gluten-free, organic, anti-GMO, everything Dr. Oz pushes, etc. Meanwhile, evidence-based approaches to the issue have not yet produced a diet that is optimal, practical, and that provides the level of enjoyment that we're used to from food. I personally think that Soylent is off to a promising start, although it has a long way to go.