Background: Nursing students constitute a population group with increased risks regarding nutritional status due to the combined pressures of studying, clinical placements, economic challenges, and emerging roles as health educators. Although there is plenty of evidence concerning nutrition education of patients, the issue of nutritional status and weight management among students nurses receives limited attention from empirical studies. To address this gap, this mixed method study aims to combine quantitative dietary assessment methods with a more qualitative approach to examining the lived nutritional experience of nursing students during all four years of their undergraduate studies. Methods: The research adopted a sequential explanatory design, which involved two stages. At the first stage, a cross-sectional quantitative survey was conducted among 560 undergraduate nursing students in three university nursing schools in the UK. The survey included a validated Food Frequency Questionnaire (FFQ), a 24-hour dietary recall form, self-reported anthropometry measurements, and the Perceived Stress Scale (PSS-10). At the second stage, twenty-four semi-structured interviews were conducted, utilizing maximum-variation purposive sampling and reflexive thematic analysis, as described by Braun & Clarke (2006). The quantitative data was analyzed using descriptive statistics, independent samples t-test, and multiple linear regression analysis. Findings: Mean BMI rose significantly from Year 1 (22.8 kg/m2) to Year 4 (24.6 kg/m2) (p < 0.001). Average daily caloric consumption was less than the dietary reference intake in all years studied, beginning from Year 3 onwards. Nutritional deficiency occurred among various micronutrients, with vitamin D (26% of DRI in Year 4), dietary fiber (51% of DRI in Year 4), and calcium (55% of DRI) being most affected. Stress score was a significant predictor of BMI (beta = 0.38, p < 0.001). Identified qualitative categories include time poverty, knowledge-behavior gap, emotional eating due to clinical practice experience, financial constraint, and negative food environments within institutions. Conclusion: Nutritional decline experienced by nursing students throughout the four-year program is a systemic issue stemming from the nature of professional training and not individual knowledge or personal willfulness. Intervention should aim at changing the institutional and curricular factors responsible for nutritional vulnerability. Simply adding nutritional education to an already crowded curriculum will not help.