Four key factors in food selection

I recently got a present book from a very "sweet" person in my life. As you can understand from the way I describe the person who gave it to me the book is about foods. It is called "The 150 Healthiest Foods on Earth". I started reading the book and at the very beginning, it came a very important point where four main factors used in the quality rating of foods are listed. I just wanted to list them in this entry:
- Omega-3 fats
- Fiber
- Antioxidants
- Glycemic index