Background: While structured exercise and targeted nutrition independently improve body composition and cardiovascular health, their comparative and combined effects in already active individuals remain underexplored. This study examined the independent and interactive impacts of a Low-Carb High-Fat (LCHF) diet, 16:8 Intermittent Fasting (IF), High-Intensity Interval Training (HIIT), and Fast Continuous Training (FCT) on body fat % and resting heart rate (RHR) in physically active adults. Methods: Sixty participants (aged 24-27) were randomized into four groups in a 2 × 2 factorial design: LCHF + HIIT, LCHF + FCT, IF + HIIT, IF + FCT. Interventions lasted six weeks. Body Fat Percentage and RHR were measured pre-and post-intervention. Two-way ANCOVA was used by controlling for pre-test measures for analysis. Results: All groups exhibited modest reductions in body fat (1.3–2.1%) and RHR (3-5 bpm). However, no statistically significant main effects were observed for diet or training, and the diet × training interaction was non-significant, though a trend toward interaction for body fat percentage (p = .096) was noted. Conclusion: Both dietary and training strategies showed comparable benefits, suggesting that in well-trained individuals, short-term interventions may produce limited differential effects due to pre-existing adaptations. The findings highlight the value of flexible, preference-based approaches for sustainable health outcomes. Longer trials in more diverse populations are warranted to clarify the potential synergistic effect.