About two years now, and I&#x27;d been doing it less strictly &#x2F; on-and-off for a year and a half before that.<p>I&#x27;ve definitely noticed feeling much more focused and productive since starting, and it also helped with dropping from 210 to a bit over 150 pounds in the first few months of 2014.<p>Also anecdotal, my cofounder at my current startup Cyph has been on keto for close to a year now, and in that time has had a heart condition almost entirely vanish and his body fat drop to something like 6%.