Some people concerned about gaining weight avoid nuts because of their high calorie count and they miss out on the associated health benefits. But researchers from the University of Toronto say those fears can be put aside since eating nuts has not been linked to weight gain.
Researchers pooled the results from more than 100 clinical trials that involved more than half a million participants to compile their findings. It is believed to be the most comprehensive review of the available data on the subject. They discovered the concerns about weight gain and nuts are unwarranted and published a report stating such in the journal Obesity Reviews.
"Overall, we found there is no association between nuts and weight gain, and in fact some analyses showed higher nut intake associated with reductions in body weight and waist circumference," said lead author Stephanie Nishi. "This study really hits home the idea that nuts can be a good option for people with diabetes or cardiovascular risk, but also for all individuals broadly as part of a healthy eating plan, without caveats."
Scientists used the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system to evaluate the quality of the studies reviewed for the analysis.
"We found the certainty of evidence was high for trials and moderate for observational studies," said John Sievenpiper, principal investigator on the study and an associate professor of nutritional sciences and medicine at the Temerty Faculty of Medicine. "That's a good indication of no harm from nuts relative to weight gain—no more than any other foods—and there may indeed be a benefit of weight loss in addition to the other widely acknowledged health benefits of nuts."
Many modern eating plans such as the Mediterranean, Portfolio or DASH diets incorporate the healthy addition of nuts. Despite that, global consumption of nuts is well below the suggested guidelines of one serving per day. A typical serving is 28-42 grams, which equates to 1 to 1.5 ounces. That’s what generally fits in the palm of an adult hand.
"We've seen consumption of nuts increase in some areas over the last decade, especially middle- and high-income countries, but most people could better realize their benefits," said Sievenpiper, who earlier this year found that a calorie labeled is not the same as a calorie digested and absorbed when people consume almonds. He is currently running a clinical trial on heart health and the Portfolio diet, which has nuts as one of the primary pillars.
"I didn't used to eat many nuts, but now I'm surrounded by almonds and macadamias—so eating more," Nishi said. "Especially due to the evidence supporting their health benefits, but also because of their versatility in the kitchen and on the go."