Fine results when going beyond this surprisingly simple diet? (5,5)
I believe the answer is:
speed limit
'fine results when going beyond this' is the definition.
The definition suggests a singular noun which matches the answer.
'surprisingly simple diet?' is the wordplay.
'surprisingly' is an anagram indicator (a surprising ordering of the letters).
'simple'+'diet'='simplediet'
'simplediet' anagrammed gives 'SPEED-LIMIT'.
Can you help me to learn more?
(Other definitions for speed limit that I've seen before include "Flashily ignoring this may gain you points" , "Rule facing drivers" , "Legal cap on drivers" , "Driving restriction" , "maximum rate by law" .)