Put the other twist on it and realize you probably aren't using trans-fats (check the label for hydrogenated or partially hydrogenated). I'd much prefer real lard any day!
As much as fat has taken a hard rap the past couple of decades, the percentage of overweight and obese US citizens has increased greatly. If you want to look at this from a health standpoint, studies are now conflicting on whether or not saturated fat is bad for you but all do agree that trans-fats are bad.
If you're looking at wanting to offer 'healthier' options, be sure to have some tasty veggies and salads. Consider offering these as optional sides instead of fries. Serve water to all customers --so many restaurants don't anymore-- and realize the rest is up to the customer.