Avoiding alcohol and salt

I took M. de Courgivaux for his son; he looked younger and though he must have been past fifty, appeared to be no more than thirty. He had found an intelligent doctor, had avoided alcohol and salt and so had become thirty again, hardly even that because he had had his hair cut that morning.

Marcel Proust - In Search of Lost Time (1913 - 1927)

Alcohol and salt? I'm partial to both  and unlike M. de Courgivaux I look my age. Maybe more butter would help.