Economic growth has spurred rapid urbanization in Malaysia and triggered changes in diet, lifestyle, and disease trends. National studies show that a third of Malaysia’s population is overweight/obese while household expenditures on dining out grow. In metropolitan Kuala Lumpur (KL), residents navigate concepts of nutrition, body weight, and health as they dine out. Using the biocultural framework, this study examined links between body weight, diet, income, street food consumption, and nutritional knowledge through the perspectives of consumers and vendors. Altogether, 77 participants were recruited for this three-phase research. In the first phase, a survey was administered to 60 participants recruited at street food sites around KL. In the second phase, semi-structured interviews, anthropometry, and diet recalls were conducted on 13 participants. Finally, semi-structured interviews and observations were carried out on four street food vendors at their places of business. Though the findings in this research did not show statistical relationships between body weight status, income, and dining out in KL, telling diet and lifestyle trends emerged. Work mediates the lives of participants, often dictating their diet and capacity to engage in physical activity. Though most female participants work, they still bear the expectations of meal provisioning. These factors encourage the consumption of food away from home, and the commercialization and gentrification of the local street food industry. When viewed critically through the biocultural framework, these observations support the idea that trade liberalization and domestic economic policies have induced demographic changes, household transformations, and dietary adaptations among urban dwellers in KL.