I think perhaps you are getting confused with the various energy producing cycles in the body
Krebs cycle is not relevant on a low or zero carb diet
On a low or zero Carb diet, ... the body has no Carbs to break down using the Krebs cycle , think about it ....
Instead our bodies utiise two processes called GLUCONEOGENESIS...and GLYCOLYSIS to create glucose from the Fat and Protein that we consume. Think of the Icelandic Inuit who until recent times had almost zero Carbs apart from sa few seasonal berries and lived entirely on Fat and Protein from Whale , Seal and fish .
If a low or non Carbohydrate diet is followed consistently for an extended period our bodies go into a state called Ketosis .This is when in the absence of any Carbohydrate Glucose source from Glycolysis or Gluconeogenesis our bodies use a process called Ketogenesis . In ketogenesis the body produces Ketones from burning Fat, both from the fat we consume and from the fat stored around our body.
There is no Glucose or Krebs Cycle involved in the Ketogenesis process and this is the basis of the Atkins Diet and other Low or zero Carbohydrate diets .