Instead he rose at 6 a.m. for a quick breakfast before heading to the gym for a four-hour workout, including 90 minutes on an elliptical machine and an hour of weights. In the afternoon, after skipping lunch, he walked for two hours before doing repeats on the library steps. He picked at his dinner before rewarding himself for his suffering with a giant piece of pie.
When Rob healed enough to run, his routines grew ever more punishing, his body ever lighter — sometimes dipping below 100 pounds on his 5-foot-7 frame. A photograph taken of him at a swimming pool in July 2009 shows deep hollows beneath his cheekbones. Striated ropes of muscle press through his skin. His arms and legs appear as thin and brittle as sticks.
Rob's family, long in denial, knew he was in trouble. He knew it too. But even though he had begun to see a therapist, it was easier to follow his compulsions than resist.
"We would have these breakthrough moments where he would say, 'I know I have a problem, but I'm not ready to give it up yet,'" his sister said. "I always knew when he stopped calling that he was getting worse. Because then he wasn't ready to hear it."
In November 2011, Rob sustained another leg fracture, the result of what doctors said was a lack of calcium in his bones. Though he was ordered to rest for a month, he became so frenzied from inactivity that he grabbed his crutches and did hobbled laps around his parents' kitchen table.
It turned out to be his moment of clarity. He called the eating disorders recovery center at Alexian Brothers Behavioral Health Hospital in Hoffman Estates and had himself admitted.
Staffers there found that his pulse was a dangerously low 32 beats per minute, said Michelle Gebhardt, the center's clinical coordinator. Their No. 1 job was to stabilize Rob — one of the few males to enter the program — by controlling his exercise and encouraging him to eat.
That turned meals into high drama. On one of his first days, he was presented with a modest portion of scrambled eggs he dubbed "Mount Eggerest." He could swallow only half. Another time he refused to eat until he was given a ham sandwich; he then declined to finish it.
Finally, Rob recalled, one of his fellow patients had had enough, telling him when he arrived for dinner: "If you sit here you better eat all your food because you are really triggering us with all your crap."
Therapy and reflection eventually convinced Rob, who was diagnosed with a condition known as eating disorder not otherwise specified, that he needed to change. He yielded to the program and spent a few weeks putting on weight before transferring to Rogers Memorial Hospital near Milwaukee, home to a rare males-only eating disorders program.
His task there was to excavate the psychological turmoil that lay beneath his behavior — the desire for control, the need to feel special, even the fear of becoming an adult — and reset his mind and body to healthy habits.
It wasn't easy. To remind himself of happier days, he hung a photograph taken a few months earlier at his sister's wedding rehearsal dinner. The image showed him standing behind his parents and smiling, his skin stretched tightly over the bones of his face.
His roommate asked what he thought of the picture. Rob said he thought he looked pretty good.
"When I see that, I don't see 'good' at all," his roommate said. "I see death."
In his three months at Rogers, Rob said, he learned to take a more realistic view of himself and gain more control over his eating and exercise habits. He put on about 45 pounds in treatment and now follows a diet worked up by a nutritionist, dining at appointed times even if he isn't hungry (his long periods of starvation scrambled the neural circuitry that governs hunger — a common side effect of an eating disorder).
He works out cautiously, lifting weights with his father lest he get carried away. On a recent Sunday morning he went for a slow walk around the block, the only form of cardiovascular exercise he allows himself.
"Sometimes there's the urge to hurry up," he said, strolling past well-watered lawns and vibrant flower beds. "It's a little battle. I usually win."
Le Grange, the University of Chicago expert, said males are so scarce in eating disorder studies that there is no good data about their chances for long-term recovery. Indeed, while Rob today looks fit and healthy, he says he'll have to be wary of backsliding for the rest of his life.
For now, though, he has managed to quiet the voice inside him with the mantra he took away from treatment: He is more than his body.
"There are so many other things that set me aside," he said. "I have my goals and aspirations, like wanting to be a counselor. What I do physically will not be the defining characteristic for me."