All food contains protein. If you are consuming adequate calories from a variety of foods, you are getting enough protein.
Here are some foods along with their protein amounts:
Sweet potato, 1 cup cooked, 4g
Kale/collards/chard/spinach, 8 ounces (about 1 cup), boiled, 8g
Romaine lettuce, 2 cups, raw, 2g
Tomato, 3 inch, raw, 2g
Brown rice, long grain, 1 cup cooked, 5g
Oatmeal, cooked with water, 1 cup, 6g
Popcorn, 2 cups, air-popped, 2g
Red potato, baked, 3.5 inch, 7g
Lentils, 1 cup cooked, 18g
Kidney beans or black beans, 1 cup, boiled, 15g
Peas, frozen, boiled, 1/2 cup, 4g
Almonds, 1 ounce, 6g
Raisins, 1 small box, 1g
Orange, 2.5 inches, 1g
The Dietary Reference Intake (DRI) for protein for a 120-pound adult is 43.5 grams/day (0.8 grams per kilogram of body weight). For a 180-pound adult it's 65 grams/day.
If I ate just the items in bold, I would surpass my protein requirements for the day. And I would not be eating meat or any other food of animal origin. I wouldn't even be eating any soy products.
In the US, there is a greater risk for getting too much protein than for getting too little. Anyone with compromised liver or kidney function (e.g many people with established diabetes or hypertension) are put upon to rid the body of excess nitrogen in the protein's amino acids. And there's that ominous graph showing the more protein you eat, the more calcium you excrete.