My mother visited back with her sister (who lived in the South) many years ago, and her comment at the time (this would have been, keep in mind, probably the early 70's) was that it seemed like they put sugar in everything.
I agree to an extent, but I think that is over-accentuated as a result of sweet tea. Sweet tea includes a LOT of sugar. The higher extreme tends to be what a few of my friends have referred to as "church sweet," which is the extraordinarily sweet tea made by the old ladies in the local churches.
IME, a LOT of southern meals lean on copious amounts of savory vegetables. We eat more meat nowadays due to accessibility, but meat was generally more of a special occasion thing. Despite how many restaurants emphasize the meat, that's often the "special side" in Southern cuisine. The vegetable or fruit dishes are where it's at! However, we do use a lot animal fat (and butter!) to flavor our dishes. Southern green beans, for example, are often slow cooked with fatback, salt pork, or some other variation of lardon.
I can tell you one thing that non-Southerners put sugar in that most Southerners do not:
cornbread. In the South, cornbread is savory and not sweet. Many Southerners even complain that cornbread outside of the South more closely resembles a sweet "cake" than what we consider proper savory cornbread. I also know that expat Southerners and non-Southerners often have difficulties replicating Southern cornbread, and there is a reason for that: the corn meal. Yes, the South uses different corn meal than you can find elsewhere in the United States and likewise here in Austria. Southern corn meal is naturally sweeter and thus doesn't need sugar added for making cornbread. (IME, honey will typically be favored over sugar to sweeten cornbread.) This is why I sometimes have my relatives ship me cornmeal from home. It makes a real difference in taste.