Am I losing my mind or does this comment have nothing to do with its parent ? <| sep |> When people say that CICO doesn ' t work they usually point to evidence from their own experience . However the issue isn ' t with CICO or even the CI part . Calculating CO is way more difficult than most people particularly in this sub like to admit . Every person ' s metabolic rate is different . We can use charts that show averages but that isn ' t the actual number your body is burning . Fitbits and other devices also use population averages . So nailing down your actual CO is incredibly difficult . So even people who are meticulous about their CI can easily be off on the CO by a few hundred calories a day which means they don ' t see the expected results . Therefore in their mind , CICO doesn ' t work .