Non-specific chronic low back pain (nCLBP) has been associated with nutrition. Yet, it is not clear how nutritional factors and nCLBP relate to one another. Therefore, the aim of the present study was to investigate differences in diet quality and dietary intake levels between nCLBP patients and healthy controls (HCs) and to explore the association between nutritional factors and pain sensitivity in nCLBP. In this case-control study, 106 participants (i.e., n=53 nCLBP and n=53 HCs) were recruited and completed a 3-day food diary to assess their dietary intake, which allowed to generate individual diet quality scores, (i.e., the healthy eating index-2015 and dietary inflammatory index). Additionally, each participant underwent an experimental pain assessment (quantitative sensory testing) and filled out self-reported pain questionnaires. Compared to HCs, the nCLBP group showed significantly lower diet quality, higher inflammatory scores, and a lower intake of total protein, total fat, dietary fibre, omega-3 fatty acids, vitamin B6, vitamin A, beta-carotene, vitamin E, and magnesium. Pain sensitivity mainly showed a negative correlation with nutritional intakes known for anti-inflammatory properties (i.e., vitamins E, D, A, B6, B12, and zinc). Interestingly, total fat, cholesterol, saturated, and monounsaturated fat intakes were found to be inversely associated with pain sensitivity. Overall, patients with nCLBP have a lower diet quality, eat more pro-inflammatory, have less intake of nutrients known for their anti-inflammatory and anti-oxidative properties, and drink less water compared to HCs. Accordingly, pain sensitivity was mainly found to be positively associated with pro-inflammatory dietary intake. PERSPECTIVE: This study emphasizes the association between a pro-inflammatory diet and non-specific chronic low back pain (nCLBP). Among nCLBP patients, positive association between increased pain sensitivity and the pro-inflammatory potential of a diet, highlighting the potential for individualized pain management strategies and leading to the development of novel therapeutic methods.Copyright © 2023. Published by Elsevier Inc.