The patient takes vitamins and minerals in doses recommended by most physicians, and gets plenty of exercise.
The patient eats a reasonably healthy diet. However, the patient depends to a large degree on imported food, which has become very expensive, and while the patient could grow plenty of home grown food, the patient hasn’t been planting enough lately to sustain present and future dietary needs. So the patient is hungry, and losing weight
The patient is mysteriously ill. Upon examination, it appears that the patient has been slowly poisoned. The patient’s immune system and general state of health might have been sufficient to cover the symptoms of the poisoning longer, except for the strain imposed by the recent hunger and weight loss. The symptoms have been coming on for sometime, but only recently have they become indisputable.