摘要:Background: Dietary and lifestyle habits constitute a significant contributing factor in the formation of anthropometric and biochemical characteristics of overweight and obese populations. The iMPROVE study recruited overweight and obese Greek adults and investigated the effect of gene–diet interactions on weight management when adhering to a six-month, randomized nutritional trial including two hypocaloric diets of different macronutrient content. The present paper displays the design of the intervention and the baseline findings of the participants’ dietary habits and their baseline anthropometric and biochemical characteristics. Methods: Baseline available data for 202 participants were analyzed and patterns were extracted via principal component analysis (PCA) on 69-item Food-Frequency Questionnaires (FFQ). Relationships with indices at baseline were investigated by multivariate linear regressions. A Lifestyle Index of five variables was further constructed. Results: PCA provided 5 dietary patterns. The “Mixed” pattern displayed positive associations with logBMI and logVisceral fat, whereas the “Traditional, vegetarian-alike” pattern was nominally, negatively associated with body and visceral fat, but positively associated with HDL levels. The Lifestyle Index displayed protective effects in the formation of logBMI and logGlucose levels. Conclusions: Dietary patterns and a Lifestyle Index in overweight and obese, Greek adults highlighted associations between diet, lifestyle, and anthropometric and biochemical indices.