The advice to drink eight glasses of water a day has been repeated so often that most people assume it rests on research. It does not. The figure appears to trace back to a recommendation from the 1940s which noted, in the same paragraph, that most of that water is already present in prepared food. That second half dropped away and the number survived on its own. This does not mean hydration is unimportant. It means the specific figure carries no particular authority, and that thirst, for a healthy adult in an ordinary climate, is a reasonably good guide.
The author's attitude toward the eight-glasses rule is best described as
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Correct answer to question 30 (Paragraph Comprehension): sceptical of the figure but not of hydration
Method
The author dismantles the number's pedigree but then explicitly says this does not mean hydration is unimportant. That sentence is there precisely to block the stronger reading offered by the first choice.
Updated: November 2026
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