Snacking on tree nuts like pistachios, and almonds does not lead to belly fat, rather they help in better weight management and are a more efficient source of energy, according to a study.

As tree nuts are high in calorie and fat content, a common misconception persists that eating nuts causes weight gain. But various studies have shown that eating tree nuts, like pistachios, daily is an easy way to experience a flavourful, nutritious, and portable snack that can reinvigorate a person.

To explore further, researchers from Vanderbilt University Medical Center in the US, fed 84 young adults (22-36 years old) who had at least one metabolic syndrome risk factor (e.g., high blood pressure, high blood glucose, excess body fat around the waist, or abnormal blood cholesterol levels) either a snack of one ounce of mixed, unsalted tree nuts (including pistachios) or one ounce of a carbohydrate snack (like unsalted pretzels or graham crackers) twice per day for 16 weeks.

Without the study participants making any other changes to their diet (without restricting calorie intake) or lifestyle habits (without changing physical activity habits), researchers saw a 67 per cent reduction in metabolic syndrome risk for females and a 42 per cent reduction in risk for males who ate tree nuts.

Participants eating one ounce of mixed tree nuts two times per day (including pistachios) had no change in their energy intake or body weight over the 16-week study period.

Further, in female participants, there was evidence that eating the mixed tree nuts led to reduced waist circumference (abdominal fat), a key risk factor for metabolic syndrome, diabetes, and heart disease.

In male participants, there was evidence that eating the mixed tree nuts led to reduced blood insulin levels, another important risk factor.

Participants eating tree nuts were also able to use fat for energy more efficiently compared to a carbohydrate snack, which may explain why the group eating tree nuts, like pistachios, did not increase body weight or body fat during the study period, said the team in the paper published in the journal Nutrients.

“We specifically designed the study to be able to investigate the independent effects of eating tree nuts on body weight by ensuring that the number of calories the participants ate during the 16-week intervention period matched the number of calories they expended each day, which is one of the overall strengths of the study design and results,” said Heidi J. Silver, from the varsity.

“This carefully designed and well-controlled study shows that eating tree nuts, like pistachios, does not have to lead to weight gain and can be an important part of anyone’s self-healthcare routine in 2024,” she explained.