Rinse and drain clams if using canned, or steam fresh clams until cooked and set aside.
Dice the potato, carrot, celery, and onion into small, uniform pieces for even cooking.
In a medium saucepan, heat the olive oil over medium heat and sauté the onion, garlic, celery, and carrot until they begin to soften, about 3-4 minutes.
Add the diced potato along with a splash of water or low-sodium broth, and cook for another 5 minutes until the potato starts to become tender.
Pour in the low-fat milk and a little water or broth (about 1/2 cup) to achieve your desired chowder consistency. Stir in the fresh thyme and season with salt and pepper.
Gently fold in the clams and let the chowder warm through for another 3-4 minutes. Do not boil once the milk is added to prevent curdling.
Finish with a sprinkle of fresh parsley, adjust seasoning to taste, and serve warm.