Here are some of the most common types of protein bars in the United States. Note that while these are the most common, not all protein bars are produced by one company. What Are Protein Bars? In short, a protein bar is a chocolate bar, or a bar made of cocoa, and has one or more of these ingredients: Protein Powder, Peanut Butter, Cocoa Butter, Cocoa Extract, Salt, Stevia Extract, Natural Flavor, and Flavoring. What Is Stevia Extract? Sucrose, sugar, and the sugar alcohols glucose and fructose are the major sources of dietary sugar. For an added sweetness, some flavors are added to the protein bars. Why Is There Such A Strong Connection Between Protein and Weight Loss? In the past, the focus on protein was related to weight loss or muscle building. Now, the focus is to lose fat and lose weight. However, that doesn't mean that there is a direct cause-and-effect relationship. Rather, there are several theories that can explain the connection between diet and weight loss. The research shows that weight loss is more effective with the diet that you follow, and that the more you follow a certain diet, the better your results will be. There are many ways to lose weight and many ways to get a better result. It all depends on what is your goal.