A new study adds to growing evidence that nuts – once considered too fattening to be healthy – may, in fact, help keep weight down, on top of offering other health benefits.
Researchers found that study participants who ate the most tree nuts – such as almonds, Brazil nuts, pistachios and walnuts – were between 37 and 46 per cent less likely to be obese than those who ate the fewest tree nuts.
People who ate the most nuts were also less likely to have metabolic syndrome, which is defined as having three or more conditions associated with heart disease and diabetes risk.
The study, which was published online in Plos One, was partially funded by a grant from the International Tree Nut Council Nutrition Research and Education Foundation.
In another recent study that the foundation also funded, researchers found that people who reported eating the most nuts were less likely to die over a 24-year period than those who ate the fewest nuts.
While such evidence cannot show that nuts cause the differences seen between people who love them and those who do not, there are reasons to believe nuts provide a direct benefit, said Dr Joan Sabate, the new study’s senior author from Loma Lind University in California in the United States.
For example, nuts are high in unsaturated fat, which is known as ‘good’ fat, rather than the ‘bad’ saturated fat in animal products. The high protein content of nuts may also lead people to feel fuller and eat less unhealthy food. Nuts also contain a host of other nutrients and beneficial plant chemicals.
For the study, the researchers used data on the diets of 803 men and women in the United States who were already enrolled in another study. Overall, those who ate a lot of tree nuts – about 16g per day – were just a little over normal weight, on average compared with those who ate few or no nuts and were seriously overweight or obese.
A normal body mass index (BMI) – a measure of weight in relation to height – for an adult falls between 18.5 and 24.9. Overweight people have a BMI of between 25 and 29.9 and a BMI of 30 or more is considered obese.
Participants who ate the most nuts have an average BMI of about 27 while those who ate the least – less than 5g of tree nuts per day – had an average BMI of 29 to 30.
The researchers also found that a third of the participants had metabolic syndrome.
For every one-ounce serving of tree nuts consumed per week, however, a person’s risk of having metabolic syndrome dropped by 7 per cent.