When the government artificially caps the prices for products, it forces the manufacturers to reduce their productions costs. For food, they can decrease the size of an item. The manufacturer could also be less selective in the quality-assurance. Under rent control, landlords are more likely to neglect the maintenance of their buildings.
Undervaluing medical care makes the doctors over-burdened with issues that would not otherwise warrant their time. This devaluation results in exceedingly long wait times. Cancers grow inoperable and the health of patients deteriorating in the meantime. There is also a concomitant deterioration in the quality of treatment from the overworked doctor.