Polyphenol intake is associated with a reduced risk of cancer, cardiovascular diseases, diabetes, immune disorders etc. The content and bioavailability of polyphenols are affected by applied food processing techniques such as heat and cold processing, and peeling. This preliminary study determined total polyphenol intake from fruit and vegetables in 10 vegan and omnivore participants before and after food processing. Participants completed a survey with basic demographic and anthropometric data and a three-day diet diary (two working days and one weekend day). The program for calculating nutrients on the basis of food intake was supplemented with total polyphenol levels in unprocessed and processed fruit and vegetables obtained from the literature. Vegans had a significantly higher intake of carbohydrates (69 E%), while omnivores had higher intakes of total, saturated, monounsaturated fat, and a lower fiber intake. Both subgroups had a lower intake of Zn than adequate levels, and vegans also had lower intakes of K and Ca. Inadequate intake of vitamins A, B9, D, and E was noted, and the deficient intake in vegans was compensated for by supplementation. The vegan diet resulted in almost two times higher intake of of polyphenols from fruit and vegetables compared to the omnivore diet (677.8 vs 357.0 mg/day), but omnivores caught up on it with an increased polyphenol intake from coffee (576.0 vs 160.0 mg/day). Total daily intake of polyphenols from fruit and vegetables, coffee, chocolate, cocoa, and tea did not differ much between subgroups: 1011.0 mg in the vegan vs 1017.3 mg in the omnivore subgroup. The greatest drop in polyphenol intake following food preparation was observed in subjects which consumed foods (brussel sprouts, sweet pepper, zucchini) prepared using techniques that lead to biggest losses, e.g. boiling in water.