Although considerable research confirms the nutritional value of tree nuts and legumes, many Americans are still wary of their high-fat and high-caloric content. A 2013 PREDIMED study of 7,210 men and women (mean age of 67) reveals, however, that nut consumption is inversely associated with the prevalence of general obesity, central obesity, metabolic syndrome and diabetes in subjects at high cardiovascular risk.
Meanwhile, a 2007 meta-analysis in the Journal of Nutrition concluded that many of the calories from tree nuts and peanuts are not absorbed by the body. This meta-analysis reported epidemiological studies showing an inverse relationship between the intake of nuts and body mass index (BMI).