A team from the Louisiana State University in the US found that those who ate tree nuts, including cashews, walnuts and pistachios, were slimmer and had low Body Mass Index (BMI) than those who didn't eat nuts.
The nut eaters also had higher levels of good cholesterol and lower levels of proteins linked to inflammation and heart disease and were also five per cent less likely to suffer metabolic syndrome -- a group of risk factors which together can cause stroke, diabetes and heart conditions.
Prof Carol O'Neil, who led the study, said: "One of the more interesting findings was the fact that tree nut consumers had lower body weight, as well as lower BMI and waist circumference compared to non-consumers."
"The mean weight, BMI, and waist circumference were 4.19 pounds, 0.9kg/m2 and 0.83 inches lower in consumers than non-consumers, respectively," she was quoted as saying by the Daily Telegraph.
Prof O'Neil's team looked at data from more than 13,000 men and women with 'tree nut consumers' classed as those who ate more than quarter of an ounce a day.
They were five per cent less likely to have metabolic syndrome and also had a lower prevalence of four risk factors for metabolic syndrome: abdominal obesity, high blood pressure, high fasting glucose levels and lower levels of high density lipoprotein, or the good, cholesterol.
Eating nuts was also linked with greater intake of whole grains and fruits and lower levels of alcohol an added sugar.
Dr O'Neil said: "Tree nuts should be an integral part of a healthy diet and encouraged by health professionals."
Maureen Ternus, Executive Director of the International Tree Nut Council Nutrition Research & Education Foundation, said: "In light of these new data and the fact that the FDA has issued a qualified health claim for nuts and heart disease with a recommended intake of 1.5 ounces of nuts per day.
"We need to educate people about the importance of including tree nuts in the diet."
