In 2011, Eric Ries took a two-word concept—the “lean startup”—and turned it into a manifesto, a guidebook for a burgeoning class of entrepreneurs empowered by the new proliferation of seed investors. Lean startups ran fast and cheap, testing and deploying products repeatedly until they achieved the holy grail of product market fit. As lean startups began to prosper, more money flowed into the system to fund them. This yielded what The New York Times called “fat startups.” Uber, WeWork and their ilk leveraged troves of venture capital cash to execute consumer land grabs and establish monopolistic or duopolitic market dominance. Fast-forward to today, when venture capitalists are begging startup founders to quell their cash burn and extend their funding runways—effectively trying to wean them off their gluttonous capital consumption and put them on a ruthless spending diet.