Dr. Oz&#39;s 7 Layer Fat-Fighting Dip: 4 cups shredded lettuce, 3 medium ripe avocados mashed and mixed with 2 tbsp lemon juice, 1 1/2 cup Greek yogurt mixed with 1 package low-sodium taco seasoning mix,  1 can black beans, 3 medium diced tomatoes, 2 cans sliced olives &amp; 8 oz 2% cheddar cheese