Nuts: Whether you go for cashews, walnuts, pistachios, or any of the other varieties, whole, raw nuts are a healthy high-protein snack choice. If you're concerned about calories, limit your nut intake to a handful or two, and remember that though nuts are high in fat, it's healthy monounsaturated fat, which doesn't clog arteries and is an essential part of a healthy diet. Plus, nuts are high in fiber, which when paired with their protein content, keeps you feeling full longer.