**Background:** Quick service restaurants (QSRs) have been linked to rising obesity rates globally, prompting governments in the USA and UK to mandate calorie and nutrition labelling on menus. Despite these regulations, the long-term effect of calorie labelling on fast-food purchases remains unclear, and there is limited research on the psychological and cultural factors that drive consumers to actually use nutrition information when making food choices. This study responds to calls for cross-cultural research by extending the Theory of Planned Behaviour (TPB) with health consciousness to examine determinants of buying and recommendation intentions for nutrition-labelled menu (NLM) items in QSRs.
**Methods:** A quantitative cross-sectional design was employed. Data were collected via online surveys administered through specialized data collection companies in the KSA and the UK during November and December 2022. A total of 900 surveys were distributed (450 per country), yielding 400 valid responses per country (88% response rate). The questionnaire measured attitude towards behaviour (ATT, 4 items), subjective norms (SNs, 3 items), perceived behavioural control (PBC, 4 items), health consciousness (3 items), intention to buy (3 items), and intention to recommend (3 items) using 5-point Likert scales. Items were adapted from Ajzen (1991), Shin et al. (2019), and Shin et al. (2020). Data were analysed using PLS-SEM with SmartPLS version 4, including bootstrapping with 5000 repetitions and multi-group analysis to compare the two countries.
**Key Results:** In the KSA sample, 65% of respondents were aged 21–30 years, 52% female, 60% held a bachelor's degree, and 80% were not on a specific diet. In the UK sample, 55% were aged 30–40 years, 51% female, 66% held a bachelor's degree, and 60% were not on a specific diet. Factor loadings for all items ranged from 0.737 to 0.949, exceeding the 0.50 threshold. Cronbach's alpha and composite reliability values all exceeded 0.7, and AVE values exceeded 0.50, confirming convergent validity. Discriminant validity was confirmed via cross-loadings, Fornell-Larcker criterion, and HTMT ratios below 0.85. For KSA consumers, ATT (β=0.367, t=7.530, p<0.000), SNs (β=0.267, t=5.385, p<0.000), and health consciousness (β=0.141, t=3.084, p<0.000) significantly predicted buying intention, but PBC did not (β=0.086, t=1.281, p=0.222). For UK consumers, ATT (β=0.385, t=8.184, p<0.000), PBC (β=0.327, t=6.908, p<0.000), and health consciousness (β=0.153, t=3.753, p<0.000) significantly predicted buying intention, but SNs did not (β=0.046, t=1.226, p=0.220). Buying intention significantly predicted recommendation intention in both KSA (β=0.731, t=20.746, p<0.000) and UK (β=0.779, t=24.832, p<0.000). Multi-group analysis revealed significant cross-cultural differences: the effect of SNs on buying intention was stronger in KSA than UK, while the effect of PBC on buying intention was stronger in UK than KSA. Mediation analysis showed that buying intention mediated the SNs→recommendation path in KSA but not UK, and mediated the PBC→recommendation path in UK but not KSA.
**Clinical Implications:** Health consciousness significantly predicted NLM buying intentions in both countries, suggesting that public health campaigns promoting health awareness could effectively increase use of nutrition labelling regardless of cultural context. However, the differential influence of subjective norms and perceived behavioural control across cultures indicates that interventions should be culturally tailored: in collectivist societies like KSA, leveraging social influence through community-based campaigns may be more effective, while in individualist societies like the UK, interventions should focus on enhancing consumers' sense of control and self-efficacy. Policymakers should enforce mandatory nutrition labelling in QSRs and integrate health education into broader lifestyle initiatives. International QSRs must recognize that a one-size-fits-all approach to menu labelling will not work; strategies must be adapted to local cultural values to maximize impact on healthy food choices.