In my humble opinion, you need to train your dog and not your family. I seriously doubt that she is doing this because you are not feeding her adequately. It is just fun. It is instinctual and the habit is breakable even if you do not, "catch her in the act." Dogs are not stupid. When you find something in her bed or any evidence that she has been in the trash, lead her to the trash and tell her, "No bad dog." Make her sit and look at it. Repeat, "No, bad dog." Lead her to the garbage can, put her close to it and tell her, "No, bad dog." She will get the message that your displeasure with her is because of the trash. Believe that. She does not want to displease you but she has to be made aware that you are the dominate partner and her behavior is bad.
The second aspect of the trash hunt is probably becuase she is bored. Dogs love to have treats and to be rewarded. Booda and Kong balls are awesome toys. They are sturdy rubber and will stand up to all kinds of gnawing and chewing and they have one that you put a treat inside and the dog has to figure out how to get the treat out. They will roll it, toss it, shake it, and your dog needs that kind of play and stimulation even more than the food. The key is in the hunt. Not so much the treasure.
Dogs are not people and dogs that are treated like people or even better than people become neurotic. You would not allow a two year old child to dig around in the garbage and your lab is at least as smart as a two year old.
After the disiplinary action of telling the dog, no and bad dog, get the Booda ball and play catch or put her favorite flavored snack in it. The dog will make the connection that the toy is the alternative to the garbage can and an unhappy owner.