1.吃的还可以: The food is/was not bad. 吃的=noun, synonym of food. 2. 吃得还可以: The taste was not bad. 吃得=The action of eating you have done.

If you're learning Cantonese, there wouldn't be cause for confusion - “的" (dik1) and "得" (daak1) are pronounced differently and are used differently. "的" is the possessive particle. So, "吃的" - That which you eat. ”得" is used usually like "V + 得 + description" - “吃得" - Eating (the verb) 吃的还可以 - What we ate was ok. 吃得还可以 - We ate alright. (Eating (here / there) was alright.) Hope this helps. :)