3. HARD-BOILED EGGS
Just like string cheese, a hard-boiled egg provides some protein and fat, while also being pretty low-cal, Warren says. Eat a couple for a snack or pair one with something else on this list.
Walnuts are high in fat, have a moderate amount of protein, and are low-carb, making them a solid snack for keto fans, Warren says. Plus, they’re heart-healthy. Stick to a serving size of one handful—otherwise the calories can add up fast.