Constant Content

Hi all,
Commas have me stumped again. Would you use a comma or semicolon after 'activity'?
The culprits: mindless snacking, gargantuan portions, and too little activity; combined with too much salt, sugar, starch, and grease.
Thanks

When you use a semicolon, both parts of the sentence must be able to stand on their own. Since it is a list (as denoted by the colon), you could emit the "combined with" and write as follows:

The culprits: mindless snacking, gargantuan portions, little activity, excessive salt, sugar, starch, and grease.

Just a suggestion, but the semicolon doesn't work.