It's no secret that our society is protein-obsessed. But when it comes to protein, there isn't a one-size-fits-all. The jury is still out on how much protein seniors need, for example. 1 in 3 Americans aged 51 and up aren't getting enough protein at all. The general rule of thumb? Eat around .8 grams of protein per kilogram of body weight. Athletes can feel free to add a bit more. Protein supports muscle growth, cell recovery and other essential body processes. Hummus, eggs, Greek yogurt, lean chicken breast and nuts are great sources of protein.