Jurors also saw photos Tuesday of Natalies skeletal, bruised body as Dr. Francis Garrity, a forensic pathologist, testified.
The retired Polk County medical examiner, who still does work for the county and the state, said Natalie had little soft tissue, muscle or fat when she died.
The 16-year-old weighed just 81 pounds at the time of her autopsy. Normal weight for a girl her height and age would have been 125 pounds, Garrity said.
She was in the fatal area, the lethal area, he told the jury.
Defense attorney Jennifer Larson suggested to Garrity that Natalie could have starved herself or had anorexia.
But Garrity said he was given no information that suggested Natalie had tell-tale medical signs of anorexia.