Mixed nuts are a popular snack option, and contain a good amount of protein and healthy fats. However, they are higher in calories, which could be a concern for weight loss.
This raises the questions – are mixed nuts a good choice for people looking to lose or maintain weight?
Nuts could play a role in a healthy weight loss program due to their nutritional content and overall health benefits. Studies have shown associations between nut consumption and lower risk of chronic disease, obesity and BMI.
Previous studies have typically used one type of nut, rather than a mixture of tree nuts. Tree nuts include a variety of nutrients including protein, fibre, healthy fats, vitamins, minerals and antioxidants. Nuts can vary in terms of nutritional value and beneficial compounds, so diversifying the nut variety may lead to greater health benefits.
There are concerns that the high caloric content of nuts may not suit a weight loss program. The researchers previously ran a small trial that found consuming pistachios as part of a weight loss program showed a trend towards greater weight loss compared to pretzels. To further investigate this, they designed a study to explore the impact of mixed tree nuts on weight loss, maintenance and satiety.
A 24-week randomised controlled 2-arm study took place. Participants were aged between 30-68 years with a BMI between 37-35. Exclusion criteria included thyroid disease, chronic disease, following a special diet or weight loss medication, >5lbs weight change in the previous 3 months, excessive alcohol intake, smoking and pregnancy.
The trial consisted of 12 weeks of weight loss (500kcal deficit) followed by 12 weeks of weight maintenance (isocaloric).
One group was told to consume 1.5oz (42.5g) of mixed tree nuts (almonds, cashews, hazelnuts, macadamias, pecans, pistachios and walnuts) daily. The second group consumed a portion of pretzels with the equivalent caloric content. Both groups received these snacks pre-packaged to ensure portion sizes were consistent.
Body weight, BMI, composition, blood pressure and satiety were measured at baseline, week 4, week 12 and week 24, along with fasting blood samples.
131 participants were enrolled, with 11 from the nut group and 23 from the pretzel group not completing the study. It was noted by the researchers that the original target of participants was 154, but enrolment closed due to the stay-at-home orders.
Both groups experienced significant weight loss – 1.6kg at 12 weeks and -1.9kg at 24 weeks for the nuts group and -1.5kg at 12 weeks and -1.4kg at 24 weeks for the pretzel group.
There was no difference in weight loss between the two groups. Both experienced a decrease in diastolic BP at 12 weeks.
The nut group showed significant increase in satiety at 24 weeks, as well as decrease in heart rate at 4, 12 and 24 weeks.
The researchers concluded that there was no difference in weight loss between the nut and pretzel groups. However, the nut group did maintain a lower weight and experienced greater satiety, as well as showing potential health benefits such as a decrease in heart rate.
Study limitations included the noted lower number of participants due to the pandemic’s effects. There was also a greater dropout rate in the pretzel group, and the pretzels were only matched in terms of calories, not macronutrients.
Future studies could explore this area further by using a control snack that is matched for macronutrients as well as calories, and by engaging a larger group of participants.
Wang, J., Wang, S., Henning, S.M., Qin, T., Pan, Y., Yang, J., Huang, J., Tseng, C.H., Heber, D. and Li, Z., 2021. Mixed Tree Nut Snacks Compared to Refined Carbohydrate Snacks Resulted in Weight Loss and Increased Satiety during Both Weight Loss and Weight Maintenance: A 24-Week Randomized Controlled Trial. Nutrients, 13(5), p.1512.