I just looked up the Jiffy mix online and discovered it has a lot of sugar and lard in it! You add egg and milk to make it. You can sub lower calorie milk/buttermilk and use egg white or eggbeaters, but the majority of the calories are coming from the mix. The nutritional information show 150 calories in a serving comes from the mix and 170 is baked. That is only an extra 20 calories from the egg and milk.
I think the real answer is finding a jiffy alternative for the future. I found a recipe for low fat corn bread that looked pretty good with basic ingredients. The muffins come out to 100 calories each. (If you are okay with substituting splenda for the sugar the muffins would be about 90 calories each.)
I think it would be awesome to try with real corn in it.
This puts me in the mood for Chevys Corn Tamalitos. I guess I better do more recipe hunting!