Background: In Peru, tuberculosis (TB) is perceived as a nutritional disease. This perception, alongside factors including household food insecurity, may drive the food choices of people with TB and influence treatment outcomes. Objectives: The objective of this qualitative study was to explore drivers of food choice among adults recently diagnosed with TB. Methods: The study was conducted between April and December 2016 in the Huaycán district of Lima, Peru. Structured questionnaires were administered to 39 adults with TB at the time of diagnosis and after 1 mo of treatment to characterize food security and socioeconomic status. At 1 mo of treatment, 24-h dietary recalls, enhanced by recipes obtained from local street vendors, were administered to examine patterns of food consumption and determine mean daily intake of macro- and micronutrients. Among a subset of 9 participants, in-depth interviews were used to explore dietary beliefs and food choices associated with TB. Results: Overall, 13.2% of participants were underweight at baseline, and 10.5% were overweight. At 1 mo of treatment, the mean caloric intake was 600 kcal/d over what was needed to maintain their current weight. Most of these additional kilocalories came from carbohydrates. Patients made active efforts to improve their diets during treatment, and were both receptive to, and actively sought out, nutritional advice. However, many patients reported significant unnecessary spending on questionable commercial products, such as expensive natural remedies and nutritional supplements. Conclusions: The perceived connection between TB and diet creates both opportunities and challenges for treatment providers. Nutritional counseling provided through the national TB program should promote dietary quality through foods that are locally available, inexpensive, and aligned with cultural perceptions of health and wellness.