Crunchy apple & grape salad

Ingredients

• 1 cup low fat vanilla yogurt
• 1/3 cup granulated sugar
• 1/3 cup brown sugar
• 1/2 cup mayonnaise
• juice from 1/2 a lemon
• ½ teaspoon ground cinnamon
• 2 granny smith apples, cored and diced
• 2 red delicious apples, cored and diced
• 1 pear, cored and diced
• 1 stalk celery, diced
• ½ cup slivered almonds
• ½ cup walnuts, chopped
• 2 cups seedless grapes, halved