"One need not torture himself in order to eat Seudah Shlishit. If one is stuffed from lunch (and afternoon snacks), he is exempt from Seudah Shlishit." (source)

"Long and hot summer days call for a light and refreshing seudah shlishit." (source)

"It's beginning to get dark, so we'd better begin Se'uda Shlishit. Where's the herring?" (Glinert)