If I was to say Chinese food, I bet the first thought is General Tsos Chicken. Well, there was never a General by that name in China. It's an American invention. You see during the gold rush in California, thousands of Chinese came to America to try their luck. While in America, they brought their cooking techniques but the food ingredients they were used to weren't here. So, they had to be creative and that was the start of Chinese American food.
Later, as the Asian population increased, the demand for traditional Chinese food was enormous. So immigrants grew all types of Chinese veggies.
In China, specifically Southern China (Canton region), there was an abundance of veggies. Rice was the number one crop. Southern China was known as the "Rice Bowl" of China, so the typical diet focused on veggies and rice and very little meat, if it was available at all. Meat was scarce in China, so when meat was served, it was considered a treat.
The Chinese food being served in America is American Chinese. Lots of fried food, very sweet, and salty. Veggies consisted mainly of American broccoli, carrots, canned mushroom, bamboo shoots and water chestnuts. Lots of gravy is part of the American fare.
You ask "Which is healthier," Hmmm, I'd say Chinese style because its cooked healthy by stir frying, balanced flavors and not overcooked. American Chinese, although invented using American produce and sauces, slowly developed its popularity based on the American taste which is very sweet, salty and crispy. One flavor overpowers the entire dish.
The Chinese say, spend the money on good quality ingredients, you'll appreciate the natural flavor. Adding the herbs and spices only enhance the flavor of the ingredients.
Years ago, MSG which is a flavor enhancer was used extensively with cheaper grades of meat. Due to the negative affects of MSG (allergies), very few restaurants use it in their cooking. So instead of MSG, they use a little more soy sauce.