 For example, not getting enough protein can lead to muscle loss, while a lack of fiber can cause constipation. And rather than go over each and every other diet such as the Mediterranean, the low-fat and the low-carb diets, we'd like to suggest a middle-of-the-road diet that is safe and successful. For breakfast, let's start with one cup of oatmeal with blueberries and almonds and a cup of low-fat Greek yogurt. The morning snack, that could be an apple or a banana.