Introduced for the first time back in 2010 by author and lifestyle guru Tim Ferriss, the slow-carb diet is witnessing a resurgence. But is the slow-carb diet really that healthy? What is the slow-carb diet? “It’s basically a cheat day.”Is the slow-carb diet healthy? This may help people lose weight in the short term, but it doesn’t help build long-term healthy eating habits.