Healthy diets have been characterized as responding to four universal principles-nutrient adequacy, dietary diversity, macronutrient balance, and moderation. With rising incomes, diet concerns globally have shifted from inadequacy of nutrients and lack of diversity, to lack of balance and moderation. This has occurred alongside declining rates of stunting and wasting in children under five and increasing rates of overweight and obesity across a broad age span. Calculations undertaken for low- and middle-income countries for policy and advocacy purposes of the economic cost of unhealthy diets have used nutritional status as a proxy or have made estimates of the impact of noncommunicable diseases by simply adding up known risks of individual diet factors. Both these methods have problems. This paper proposes a new methodology, taking advantage of recent, more holistic, measures of diet quality. Preliminary regression results are presented using cross-country data and the Global Dietary Recommendations Score and Minimum Dietary Diversity for women. The results suggest that diet quality variables generally have the expected signs, but there are also clear limitations of using cross-country data. The methodology could be applied in future to a limited number of broadly representative low- and middle-income countries data sets containing both diet recall data as well as measures of noncommunicable disease risk status. The analysis suggests that this work could inform policies such as the repurposing of existing agrifood policies to complement existing public health policies, to reduce the economic and health burdens imposed by unhealthy diets.