Those who ate the most nuts (5 ounces or more) per week, including peanuts, had a 25% lower risk of gall stones than those who ate the least (less than one ounce (about 1/4 cup) per month.(Amer. J. Clin. Nutr. 80:76, 2004)
According to Michael Leitzmann, an epidemiologist at the National Cancer Institute in Bethesda, Maryland, "the nuts could be decreasing insulin resistance. Or their fiber, vitamin E, magnesium, or unsaturated fats might affect the development of gall stones."
"Fiber, nuts and plant protein each lowers the risk of gall stone disease by 15 - 25 percent, but someone who combines several of them might well see a protective effect greater than 25 percent", says Leitzmann.
Harvard researchers found that patients who ate nuts at least once a week had a 40 percent lower risk of advanced macular degeneration than those who never ate them. Those who ate baked sweets and potato chips two or three times a day or more had twice the risk of people who ate those foods only once every two weeks or so. (Arch. Ophthalmol. 119:1259, 2003.)
So keep on eating nuts!