Every day was a cheat day.  Notice her prodigious consumption of soda and chips.  And all the dressing she glopped onto her salad.  Was she counting the calories?  Hell no.  Even with an over stretched, oversized stomach like Boogie2988 "2500-calorie diets leave me hungry" has, it's not hard to eat under her BMR on a keto diet.  When you weigh 600 pounds you're burning a lot of energy just to sit there.