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

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"cost of _ healthy diets\") OR (\"cost of _ health diets\"))".
• Removing quotes may allow a broader search: (( cost of _ healthy diets ) OR ( cost of _ health diets )).
• Adding a wildcard symbol may retrieve word variants: (("cost of _ healthy diets") OR ("cost of _ health diets"))*.