Background: This study assessed the possible dependencies between nutritional habits and body composition among subjects with different dietary habits. Materials: A total of 196 healthy (aged 18−50 yrs) participants were enrolled in the study and divided into 4 groups according to their diet: vegans-VEGAN (n = 53), lacto/ovo-vegetarians—VEGE (n = 52), pescatarians-PESCA (n = 28), and omnivores-OMN (n = 43). Methods: The Food Frequency Questionnaire (FFQ) was used, and body composition was assessed on the In-Body120 analyzer. Results: Our result revealed in OMN + PESCA groups a higher average consumption frequency of sweets (p = 0.024), cheese/plant cheese (p < 0.001), eggs and egg dishes/egg substitutes (p < 0.001), butter, margarine/plant margarine (p < 0.001), cream /plant cream (p = 0.018), wine and cocktails (p = 0.028), vodka (p = 0.039) and lower of natural cottage cheese/tofu/tempeh (p < 0.001), vegetable oils (p = 0.036), legumes (p < 0.001) and nuts and seeds(p < 0.001) compared to the VEGAN + VEGE groups. The body composition analysis showed significant differences in skeletal muscle mass (SMM) (p = 0.019) and the content of minerals (p = 0.048) between groups. VEGAN disclosed the lowest average values of body fat mass (BFM), percentage body fat (PBF), and visceral adipose tissue (VAT) than other studied groups. Conclusions: The body composition analysis showed mean values within normal ranges in all of the groups, but some average results of OMN, PESCA, and VEGE compared to VEGAN were not highly satisfactory (in addition to eating behavior outcomes).