Although the principles of refrigeration have been understood for thousands of years, the widespread use of mechanical refrigeration in the processing, shipping, and storing of perishable commodities began only in the 1890s. Because refrigeration facilitated the hygienic handling and storage of perishables, it promoted output growth, consumption, and nutrition through the spatial and temporal integration of markets for perishables. We estimate the impact of mechanical refrigeration on output and consumption, and hence on human nutrition, concentrating on the contribution from refrigerated dairy products, an important source of nutrients, particularly proteins and calcium. We conclude that the adoption of refrigeration in the late-nineteenth-century United States increased dairy consumption by 1.7% and overall protein intake by 1.25% annually after the 1890s. The increase in protein consumption was particularly important to the growth of the human organism. According to our lower-bound estimates, refrigeration directly contributed at least 5.1% of the increase in adult stature of the postrefrigeration cohorts, and combined with the indirect effects associated with improvements in the quality of nutrients and the reduction in illness, the overall impact was considerably larger.