It doesn't work because she doesn't count accurately.  She overestimates the portion size and therefore underestimates the calories she's eating and probably conveniently "forgets" to log certain foods.  "I had a Starbucks Latte this morning, and that's coffee, and coffee has no calories so the Latte didn't count."  But it does.  "Oh yay!  This cheesecake is only 257 calories!"  When in reality, a 2.8 ounce "serving" of cheesecake is 257 calories, but she eats the entire cake (6 servings) and logs it as one.  Therefore her 257 calorie treat is in reality 1542 calories.    So she didn't lose weight because she sucks at math and/or knowing what a portion is.  This is critical to calorie counting.  Counting calories "doesn't work" for her because she's too stupid to calculate the actual caloric content of what she stuffs into her maw or she willfully pretends that she didn't eat it.  Saying that counting calories doesn't work is the same as saying that 3*4 = "puppies are fuzzy". TL:dr She's stupid, math is hard, calories aren't real, her body is not a calorimeter, physics is fat-shaming, chemistry is a tool of the patriarchy, feel sorry for her, love her for her inner beauty