Hugo supplied a verifiable example from 1975.
The practice of consuming large servings of carbohydrates before participating in endurance sports was referred to as carbohydrate loading as early as 1963, but the colloquial term carbo-loading is more common today. When we published our entry for carbo-loading in 2008, the earliest example we were able to include was from a newspaper article published in 1980:
1980 Capital (Annapolis, Md.) 2 Oct. 1/2 For the sophisticated distance runner, the as-yet unsolved medical mysteries of the runner’s ‘high’..and ‘carbo loading’ provide the satisfaction of extending the frontiers of human knowledge.
Now, however, we have found verifiable evidence from the July 1978 issue of Yoga Journal, referring to an article published the same year in Runner’s World. We suspect that the word may turn up earlier still in Runner’s World and other specialist running publications. Can you help us find it?
Posted by OED_Editor on 9 November 2012 8.41