To examine the association between consumption of western foods purchased and consumed away from home and measures of nutrition quality: average daily caloric intake and macronutrient (carbohydrates, fat and protein) shares, for urban consumers in Vietnam, a country undergoing economic transition.

Cross-sectional observational data were collected using household surveys and 24-h food diaries. Outcome variables were individual average daily caloric intake and shares of calories from macronutrients: carbohydrates, fat and protein. The key explanatory variable was individual daily share of calories from western food purchased and consumed away from home. Ordinary least squares and multivariate regression analyses were used to examine the association between the outcome variables: caloric intake and macronutrient shares and the share of calories from western food consumed away from home.

Hanoi and Ho Chi Minh City in Vietnam.

In total, 1685 households and 4997 individuals, including adults (aged $$ \ge $$ 18 years), adolescents (aged 10–17 years) and children (aged 0–9 years).

The share of calories from western food away from home was significantly associated with higher caloric intake among male and female adults (P < 0·01), adolescents (P < 0·01) and male children (P < 0·10) and was associated with higher shares of fat for male and female adults (P < 0·01), adolescents (P < 0·01) and male children (P < 0·01).

Policymakers must be conscious of the numerous factors associated with poor nutrition quality, especially in younger Vietnamese individuals. Relevant interventions targeting at risk groups are required if nutrition improvement is a long-term goal.