Post-teneral diets containing protein have been shown to enhance the copulatory success of sterile male Mediterranean fruit flies, Ceratitis capitata (Wied.) (Diptera: Tephritidae). However, ingesting protein was also found to negatively affect male survival, in particular when males faced starvation following release in the field. Accordingly, the objective of the present study was to determine the effects of various post-teneral diets, presented to sterile males prior to release, on their subsequent ability to forage for carbohydrates and protein in the field. Using mark-release recapture and analytic biochemical methods, we found that both protein-fed and protein-deprived males foraged successfully for protein and sugar in a field enclosure when these resources were available. We conclude that protein-fed sterile males are able to exploit sources of nutrition in the release environment, and their inability to overcome starvation is not a concern for control operations using the sterile insect technique.