How to use the Switch function to look for strings

Putting in an OR isn't a problem.

SWITCH (
    TRUE (),
    CONTAINSSTRING ( [Title], "calorie control" ) || CONTAINSSTRING ( [Title], "cook & bake" ) , "Sucralose",
    CONTAINSSTRING ( [Title], "natural" ) , "Stevia",
    CONTAINSSTRING ( [Title], "sugar control" ) , "Aspertame"
)

But this isn't really any different than without the OR.

SWITCH (
    TRUE (),
    CONTAINSSTRING ( [Title], "calorie control" ), "Sucralose",
    CONTAINSSTRING ( [Title], "cook & bake" ) , "Sucralose",
    CONTAINSSTRING ( [Title], "natural" ) , "Stevia",
    CONTAINSSTRING ( [Title], "sugar control" ) , "Aspertame"
)

Hi,

This calculated column formula works

=LOOKUPVALUE(search_terms[Result],search_terms[Search string],FIRSTNONBLANK(FILTER(VALUES(search_terms[Search string]),SEARCH(search_terms[Search string],Data[Title],1,0)),1))

The search terms table looks like this

Search stringResult

Hope this helps.

The SWITCH function returns the first result that matches the first argument (in this case, TRUE). So, in this pattern, it returns the result following the first test that evaluates as being true.

More detail here:
https://p3adaptive.com/2015/03/the-diabolical-genius-of-switch-true/