Should I watch FMA before FMAB?

When It Makes Sense

• Good fit: You enjoy exploring multiple adaptations of the same source material and want to see how the 2003 series diverges from the manga, providing a richer comparative experience.
• Good fit: You have ample time and prefer a slower, character‑driven narrative that delves into original plotlines not present in the later series.

When You Should Avoid It

• Warning sign: You have limited viewing time and want the most faithful representation of the manga storyline without revisiting similar arcs.
• Warning sign: You are sensitive to tonal shifts; the 2003 series blends darker themes with a lighter, more episodic feel that may feel inconsistent with the polished tone of Brotherhood.

Pros and Cons

Pros

• Provides insight into alternative plot developments and original filler arcs that enrich understanding of the franchise’s evolution.
• Offers a nostalgic, early‑2000s anime aesthetic that some viewers find appealing and distinct from modern animation.

Cons

• Repeats major story beats, potentially leading to fatigue before starting Brotherhood, which streamlines the narrative.
• Lower production values and pacing differences may feel dated compared to the higher‑quality animation and tighter storytelling of FMAB.

Decision Checklist

• Do I have the time to watch two full‑length series before moving on to other commitments?
• Am I interested in seeing how an earlier adaptation handles the source material’s themes and characters?
• Will watching the 2003 series enhance or diminish my enjoyment of Brotherhood’s tighter plot?

Alternatives to Consider

If you prefer a single, streamlined experience, you can start directly with Fullmetal Alchemist: Brotherhood, which follows the manga closely and eliminates redundant storytelling. Alternatively, you might watch only selected episodes or arcs of the 2003 series that are highlighted in fan guides, giving you a taste of its unique content without committing to the entire show.

Final Recommendation

For viewers who value a comprehensive, comparative look at the franchise and have the time to invest, watching Fullmetal Alchemist before Brotherhood can be rewarding. However, if your priority is a concise, high‑quality adaptation that stays true to the manga, starting with Brotherhood alone is a sensible choice. As with any entertainment decision, weigh your schedule, preferences for narrative depth versus efficiency, and be prepared to adjust your plan if you find the first series isn’t meeting your expectations.