Are fatty nuts a weighty concern? A systematic review and meta‐analysis and dose–response meta‐regression of prospective cohorts and randomized controlled trials

Abstract

Nuts are recommended for cardiovascular health, yet concerns remain that nuts may contribute to weight gain due to their high energy density. A systematic review and meta-analysis of prospective cohorts and randomized controlled trials (RCTs) was conducted to update the evidence, provide a dose-response analysis, and assess differences in nut type, comparator and more in subgroup analyses. MEDLINE, EMBASE, and Cochrane were searched, along with manual searches. Data from eligible studies were pooled using meta-analysis methods. Interstudy heterogeneity was assessed (Cochran Q statistic) and quantified (I 2 statistic).

Effects of Hazelnut Consumption on Cardiometabolic Risk Factors and Acceptance: A Systematic Review

“…These findings are consistent with other studies, which have found no evidence of weight gain in the short-term following the addition of nuts to the diet [ 11 , 19 , 61 ]. In addition, a meta-analysis of three RCTs reported no change in body weight with hazelnut consumption [ 31 ].…”

“…Although nuts are high in energy and fat, observational studies report that nut consumers are leaner than non-nut consumers [ 8 , 9 ]. Additionally, longitudinal studies report nut consumption is associated with a lower risk of overweight and obesity, weight gain, and deposition of abdominal adiposity [ 10 , 11 ].…”

“…Findings on blood pressure and biomarkers of oxidation, inflammation, and endothelial function are mixed, with some showing positive effects, while others report no effect [ 13 , 15 , 16 , 17 , 18 ]. In support of observational studies, intervention studies have found that adding nuts to the usual diet results in no weight gain or less than expected weight gain given the additional calories provided by nuts [ 11 , 19 ].…”

The Regular Consumption of Nuts Is Associated with a Lower Prevalence of Abdominal Obesity and Metabolic Syndrome in Older People from the North of Spain

“…A possible reason for this low nut consumption is the belief in the older population that the composition of nuts, rich in fatty acids, is associated with weight gain. However, a systematic review and meta-analysis of prospective cohorts and randomized controlled trials published in 2021 [35] evaluating the impact of nut consumption on adiposity measures concluded that, based on current evidence, health professionals and dietary guidelines can advise a daily consumption of a 42.5 g serving, except for people with nut allergies, without an increase in adiposity or concern for an adverse on body weight control. According to previous studies carried out in other populations in the Mediterranean basin, it seems that a lower than recommended consumption of nuts is common in older people, since in a recent study [36], in individuals aged 60−69 years, the percentage of adherence to the recommendations was 34% and in individuals aged 70−79 years it was 32%, and on the other hand, in a population aged over 65 years living in Sicily, the percentage of individuals with a low consumption of nuts (average 4.3 g/day) was significantly higher (21.9%) than those with a high nut consumption (mean 39.7 g/day), which stood at 16.4% (p = 0.004) [37].…”

“…Another possible reason for the low consumption of nuts in elderly people may be related to chewing problems and dysphagia that are very common in this population group, however, should facilitate the daily consumption of small amounts (between 28.3 to 42.5 g) [35], through techniques such as crushing and incorporating them into foods that are easy to chew and swallow such as yogurts. In this way, the population mentioned before will take advantage of the beneficial properties demonstrated in the PREDIMED study [39], according to which the consumption of a Mediterranean diet supplemented with 45 g of nuts daily in an elderly population at high cardiovascular risk reduced the risk of myocardial infarction and cerebrovascular infarction and mortality from these pathologies by up to 30%, associated with improvements in the components of MetS.…”