I'm no doctor, but it seems to me that how long you eat shouldn't affect your gallbladder. Unless you were also eating at night, while sleeping, your gallbladder most assuredly would be "resting" then.
Organs don't need "rest" that I know of, not unless there is a serious digestive issue, in which case you'll be under a doctor's immediate care.
Even googling it brought nothing up, so I think you misheard something, or misunderstood something you read. Gallbladder issues are not caused by taking too long to eat.
Here's the longest list of causes I was able to find:
Hashimoto's Thyroid Disease
Low stomach acid
Food Sensitivities or Allergies
Rapid weight loss
Estrogen intake and birth control pills(estrogen increases the concentration of cholesterol in the bile)
Frequent use of Antacids
Over age 40 and increase in risk as one ages
Female especially those who have had children
Ethnicity (Pima Indians and Mexican-Americans)
High triglycerides, high LDL cholesterol, decreased HDL cholesterol,
Family history of gallbladder disease (Heredity)
Cholesterol-lowering drugs, immunosuppressive drugs
Antidepressants which slow down gallbladder contractions
Very Low Calorie Diets
Diet high in saturated fats
Diet high in refined foods and sugars
Diet low in fiber (which is what the refined diets are) and not enough vegetables
Diseases such as chronic inflammatory bowel disease, Chron's disease (ulcerative colitis is contraversial) Hemolytic anemias www.gallbladderattack.com/gallbladderdisea