WP Speed Guide 2026
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Design 18 min Updated 2026

Optimizing Themes & Reducing Bloat

How to debloat your theme or switch to a performance-focused block theme.

Optimizing Themes & Reducing Bloat

Your theme dictates the HTML structure and CSS of your site. A poorly coded theme can make it impossible to achieve a 100/100 Lighthouse score, no matter how many caching plugins you use.

The Rise of Block Themes (FSE)

In 2026, WordPress is fully committed to Full Site Editing (FSE). Block themes (like Twenty Twenty-Four and newer) are significantly faster than classic themes because they load styles only for the blocks present on the page.

Step 1: Choosing a Fast Theme

If you are starting fresh or willing to switch, choose one of these performance-focused themes:

  1. GeneratePress: The gold standard for speed. incredibly lightweight (< 30kb).
  2. Kadence: Fast, feature-rich, and modern.
  3. Blocksy: Great design and very fast.
  4. Default WordPress Themes: Twenty Twenty-Five is excellent.

Avoid: Themeforest "Multi-Purpose" themes that come bundled with 5 sliders and 3 page builders. They are often "bloatware".

Step 2: Debloating Your Current Theme

If you can't switch themes, you need to strip out the junk.

1. Disable Google Fonts

If your theme loads 10 different font weights, it slows down rendering.

  • Use OMGF (Optimize My Google Fonts) plugin to host fonts locally and preload only what you need.
  • Or switch to System Fonts (Arial, Helvetica, etc.) for instant rendering.

2. Disable Font Awesome / Icon Sets

Many themes load the entire Font Awesome library (5000+ icons) just to show a hamburger menu and a Facebook icon.

  • Use a plugin like Asset CleanUp or Perfmatters to unload these CSS files on pages where they aren't used.

3. Remove Unused CSS

This is the "Remove Unused CSS" warning in PageSpeed Insights.

  • WP Rocket has a "Remove Unused CSS" feature that generates a unique, small CSS file for each page. This is the easiest fix.

Step 3: Child Themes

Never edit your theme files directly. When the theme updates, you will lose your changes.

  1. Create a Child Theme.
  2. Add your custom PHP optimizations to functions.php in the child theme.

Conclusion

Your theme is the skeleton of your site. If the skeleton is heavy and clunky, the site will never run fast. Choose lightweight, modern themes built for the Block Editor.

Next, we will discuss Lazy Loading, a technique to prioritize the content the user actually sees.