When trying to lose weight, people come up with all sorts of complicated rules. I hear these all the time. I can't have any _______ (fat, carbs, food developed since the Paleolithic era, etc.) or I have to eat ________ (foods for a blood type, weight loss shake, etc.). These overly complicated rules and restrictions tend to increase the chance of failure and are likely not something a person can maintain for a lifestyle. Remember you are looking for a change you can maintain for the rest of your life!
How do you know what healthy real food is? My rule of thumb is asking myself "Do I recognize where my food came from?" Healthy foods generally still resemble their source. Vegetables should be recognizable from when they were growing in the garden. Meats should be recognizable as fish, beef, chicken, etc. Carbohydrates should look also be easily recognizable as rice, sweet potato, etc. If you have to look at a label to tell what is in your meal, this may not be your best choice.
This is the most important of any change you can make in your eating habits. Making this change will make it much more difficult to make any of the other dietary mistakes.