Debate has arisen over the extent of marine food consumption and by implication coastal residence among Holocene hunter-gatherers in the Cape Province of South Africa. Whereas bioarchaeological methods have been assumed to imply short-term probably seasonal coastal visits, stable carbon isotope results are held to demonstrate heavily marine food intake and almost permanent coastal dwelling. A metabolic critique of the isotope interpretation is offered, in which the suggestion is made that marine food signals are exaggerated in skeletons because of protein-induced high turnover rates. The palaeoenvironmental implications of isotope readings are shown to demonstrate a higher inland C₄ component than has hitherto been recognized. Some enrichment of skeletons may well result from terrestrial rather than marine food consumption.