The consumption frequency and portion size of discretionary snacks are thought to contribute to a greater food intake and risk of overweight or obesity in the developed world but evidence from epidemiological studies is inconclusive. To investigate this, we systematically evaluated evidence on the effects of discretionary snack consumption on weight status, energy intake, and diet quality. Articles involving discretionary snacks reported against the outcome measures of any primary, peer-reviewed study using human participants from free-living conditions for all age groups were included. A total of 14,780 titles were identified and 40 eligible publications were identified. Three key outcomes were reported: weight status (n = 35), energy intake (n = 11), and diet quality (n = 3). Increased discretionary snack consumption may contribute modestly to energy intake, however, there is a lack of consistent associations with increased weight/BMI. Although cross-sectional analyses offered conflicting findings, longitudinal studies in adults showed a consistent positive relationship between discretionary snack intake and increasing weight or body mass index. Given that experimental findings suggest reducing the size of discretionary snacks could lead to decreased consumption and subsequent energy intake, food policy makers and manufacturers may find it valuable to consider altering the portion and/or packaging size of discretionary snacks.

中文翻译：

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随意零食消费对总体能量摄入、体重状况和饮食质量的影响：系统评价

在发达国家，随意零食的消费频率和份量被认为会导致食物摄入量增加以及超重或肥胖的风险，但流行病学研究的证据尚无定论。为了调查这一点，我们系统地评估了随意零食消费对体重状况、能量摄入和饮食质量影响的证据。涉及随意零食的文章包括针对任何主要的、同行评审的研究的结果测量，该研究使用来自自由生活条件的所有年龄段的人类参与者。共确定了 14,780 个标题，并确定了 40 个符合条件的出版物。报告了三个关键结果：体重状况（n  = 35）、能量摄入（n  = 11）和饮食质量（n  = 3）。增加随意零食的摄入量可能会适度增加能量摄入，但与体重/BMI 的增加缺乏一致的关联。尽管横断面分析提供了相互矛盾的结果，但成人纵向研究表明，酌情零食摄入量与体重或体重指数增加之间存在一致的正相关关系。鉴于实验结果表明，减少随意零食的尺寸可能会导致消费量和随后的能量摄入量减少，食品政策制定者和制造商可能会发现考虑改变随意零食的份量和/或包装尺寸很有价值。