You would expend more than 800 calories from breathing alone at the weight of 125lb.<p>The Base Metabolic Rate in the cited paper is still much higher than that even for people whose metabolism slowed down.<p>Normally, it&#x27;s calculated as 
(9.99 x weight_in_kg) + (6.25 x height_in_cm) – (4.92 x age) – 161 for women.<p>So for her (assuming she is 5&#x27; tall and late 20&#x27;s), to remain at normal weight and not move at all it would have been 
(9.99 x 56.699) + (6.25 x 152.4) – (4.92 x 27) – 161 = 1225<p>This is without any exercise. She must have missed some source of calories.