Many people have issues with offering food when trying to change a behavior. Holding a piece of food in front of your dog to coax an already learned behavior is bribery.
Offering a reward for complying with a behavior or activity that a dog does not want to do is creating a positive association. Of course how and when you offer the reward is very important. Once a positive association is created and depending on how much a dog hates a particular activity or behavior will factor in on how long and at what intervals the reward is given.
Some humans tend to think of exchanging a food reward for complying with a disliked behavior or activity, as losing power; they opt to force their dog to do whatever it is they don't want to do. When you force a dog to do something that they don't want to do, you can end up in a huge heap of trouble. The fallout behaviors from forcing a dog can be anything from fear to aggression, depending on the dog.
Let's stay on nails as it is such a common dislike for dogs. Say your dog hates having their nails done. Each time seems to get harder and harder; you hold them more firmly and the more firmly you hold them the more they struggle. Soon the mere sight of the clippers sends your dog running for cover; which means that their adrenaline is released in their body, not good. Adrenaline causes the fight or flight response, stress. So why not try to create a more positive association around nail cutting? It may never be enjoyed or desirable but it can most definitely become an experience that does not trigger a stress response.
Penny had a bad association with nails so we started just like I would with a puppy, slowly. Just the visual of the dremel produced treats; then turning it on, touching her foot with it and moving onto one toe, one treat. We are up to a full foot for a treat; we are most definitely making progress.
Anything can be a negative for our dogs; an activity or behavior that they just dislike. Turning it around can take time and patience. But with baby steps and dedication you can change how your dog feels about the less enjoyable things in life.