Manufacturers of protein shakes may claim that their products help decrease body fat or promote weight loss, but protein shakes aren't a magic bullet for weight loss.

Replacing meals with protein shakes may help you reduce your daily calories, which can help you lose weight. But eventually you will need to start eating solid food again, which may cause excess weight to return if you don't choose wisely. And if you rely too heavily on protein shakes to replace regular meals, you'll miss out on the nutritional benefits of whole foods.

Since protein contains calories, consuming too much can actually make losing weight more difficult — especially if you drink protein shakes in addition to your usual diet, and you're not exercising.

The average adult needs 46 to 56 grams of protein a day, depending on weight and overall health. As long as you're eating a healthy diet, adding extra protein — either through protein shakes or other sources — isn't necessary.

Remember, the key to losing weight is burning more calories than you consume. Choose healthy foods — such as fruits, vegetables, whole grains and lean sources of protein — and include physical activity in your daily routine.