Perhaps you should try some spelling variations:
"cost of _ healthy diets" » "cost of _ healthy adults", "cost of _ health diets", "cost of _ healthy dies"
"cost of _ healthy dies" » "cost of _ healthy ties", "cost of _ healthy aims", "cost of _ healthy days", "cost of _ health dies"
"cost of _ healthy city" » "cost of _ healthy cities", "cost of _ health city"
"cost of _ healthy diet" » "cost of _ health diet", "cost of _ healthy die"

Try widening your search to All Fields.

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (("cost of _ healthy dies") OR ((((("cost of _ healthy diets") OR ("cost of _ healthy diet"))) OR ("cost of _ healthy city")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"cost of _ healthy dies\") or (((((\"cost of _ healthy diets\") OR (\"cost of _ healthy diet\"))) or (\"cost of _ healthy city\"))))".
• Removing quotes may allow a broader search: (( cost of _ healthy dies ) or ((((( cost of _ healthy diets ) OR ( cost of _ healthy diet ))) or ( cost of _ healthy city )))).
• Adding a wildcard symbol may retrieve word variants: (("cost of _ healthy dies") or ((((("cost of _ healthy diets") OR ("cost of _ healthy diet"))) or ("cost of _ healthy city"))))*.