Frozen Custard vs Ice Cream... What's the difference?

This weekend Geoff and I got us a little surprise day-date.  Both of our kids went to play with friends at the same time, so we went took ourselves out to eat shark tacos,  to see a movie, and to eat some frozen custard--usually we'd go for fro-yo but we had a buy one get one free coupon.

Frozen custard is so good. I love Sheridan's and Culver's  even though I usually can't eat it, because usually my stomach gives me major negative feedback in the forms of ridiculous cramps and aches. But it's still good.
I've always wondered what the difference between frozen custard and ice cream is. So tonight I did a little googeling.  Apparently frozen custard has eggs in its mix and its much denser, no air is whipped into it as it freezes, that is why its extra thick and creamy. BUT it also means it has WAY more CALORIES.. you know those evil things that sneak into your closet at night and make your clothes shrink?   Anyway, I looked up the nutritional info and a single scoop cone of Culver's frozen custard (147g serving size) has 330 calories and 18 grams of fat.  Comparatively, a Small Vanilla Cone from Dairy Queen has 230 calories and only 7 grams of fat in its close to the same size (142g) serving.  If I go for ice cream I usually just head up to McDonald's because it's closest to my little blue house. So I looked up a McD's cone, they happen to serve reduced fat ice cream and their cones  have 170 calories and only 4.5g of fat. 

Anyway Culver's is yummy but I don't think  its worth 160 calories more than a good ole McDonald's cone.   And now that I know a cone has less than 200 calories, I can feel less guilty about treating myself after a long hot day of laying by the pool every once in a while.