Here are a few options for a WordPress post tag description for “永續飲食” (Sustainable Diet) in Traditional Chinese, varying slightly in tone and focus:

**Option 1 (Concise & General):**

> 關注環境、健康與社會公平的飲食方式。了解如何透過飲食選擇，實踐永續發展。
>
> *(Concerned with environmental, health, and social justice in your diet. Learn how to practice sustainable development through your food choices.)*

**Option 2 (Emphasizing Practicality):**

> 探索永續飲食的秘訣和食譜，包括減少食物浪費、支持在地生產、選擇對環境友善的食材，以及關注食物的社會影響。
>
> *(Explore the secrets and recipes of a sustainable diet, including reducing food waste, supporting local producers, choosing environmentally friendly ingredients, and paying attention to the social impact of food.)*

**Option 3 (Focusing on Benefits):**

> 享受美味、健康、同時對地球友善的永續飲食。 了解如何改善您的飲食，減少碳足跡，並為更美好的世界做出貢獻。
>
> *(Enjoy a delicious, healthy, and planet-friendly sustainable diet. Learn how to improve your diet, reduce your carbon footprint, and contribute to a better world.)*

**Option 4 (Slightly more formal):**

> 永續飲食是一種綜合性的方法，旨在最大化食物系統的環境、社會和經濟效益，同時最小化其负面影響。 此標籤囊括了相關文章，提供實用的指南和建議，助您实现更具永續性的飲食習慣。
>
> *(Sustainable diet is a comprehensive approach aimed at maximizing the environmental, social, and economic benefits of the food system while minimizing its negative impacts. This tag encompasses relevant articles, providing practical guides and suggestions to help you achieve a more sustainable dietary habit.)*

**Key Considerations When Choosing:**

* **Target Audience:** Who are you writing for? Are they beginners or already familiar with the concept of sustainable eating?
* **Content of the Posts:** What kind of content will be tagged with “永續飲食”? Recipes? News articles? Educational guides?
* **SEO:** Consider using keywords that people might search for, such as “永續飲食”, “環保飲食”, “健康飲食”, “食物浪費”, etc.
* **Length:** WordPress tag descriptions are generally best kept concise.

Choose the description that best suits your needs and the content you will be tagging! You can also edit it later if you decide to adjust your approach.