Protein powder can be a tool in a successful weight-loss plan, but it isn't a magic bullet when it comes to trimming pounds. You can use it to support muscle repair after a hard workout and to boost your protein intake when you just can't get enough from whole-food sources. Adding protein powder to your diet without cutting calories will not help you lose significant weight, though. You must use it as part of an overall low-calorie plan, along with exercise, to get weight-loss results.
Milk-Based Powders Help With Weight Loss
Powders come from a variety of sources, including whey, soy, brown rice, peas, egg white and hemp. Which type you choose depends on your personal preferences, but whey and casein, the two primary proteins found in milk, have proven fat-loss properties. In a 2011 issue of the Journal of Nutrition, researchers from the Beltsville Human Nutrition Research Center in Maryland compared results from participants who either used whey protein, soy protein or carbohydrate supplements two times per day and weren't directed to change their diet. After 23 weeks, those who drank the whey protein experienced smaller waist circumferences and lower levels of hunger hormones, in addition to slight decreases in weight despite not following a specific reduced-calorie plan.
Whey protein helps to drive muscle anabolism, or growth, notes a meta-analysis published in the 2013 issue of Nutrition and Metabolism. When dieters trim calories, the body often burns valuable lean muscle mass for energy. The growth-inducing qualities of whey help spare muscle loss when you decrease calories to lose weight, so you lose more fat. Casein seems to have the same effect, and researchers aren't sure which is superior, so you might get benefits by combining them both. Milk proteins also help control hunger to make maintaining a low-calorie diet easier.
Nonmilk Protein Powder and Weight Loss
Extensive research hasn't been done on weight loss and other types of protein powders. A 2013 issue of Nutrition Journal did test the muscle-sparing effects of whey protein vs. rice protein consumed after exercise training three times per week for eight weeks and found that both types had similar effects on muscle recovery and improvements in the ratio of lean body mass to fat. And, in 2007, research published in the Journal of the American Dietetic Association found no weight-loss benefits from consuming soy-protein-rich foods, as did the aforementioned study from the Journal of Nutrition.
Protein Powder in a Weight-Loss Plan
Lean meat, egg whites or white-meat poultry are examples of whole-food proteins that contain nutrients in addition to the protein. When you have a choice, opt for whole-food protein because it's essential for satiety, a healthy body and weight loss.
Protein powder does serve as a quick way to fit in this nutrient when you don't have time or access to whole foods, such as on a busy morning or immediately after a workout. Replacing a high-calorie breakfast with a smoothie that includes protein powder is one way to use it for weight loss. You may also blend the powder into milk or water for a convenient and easily digested post-workout snack. The protein ingested after working out helps your muscles repair more quickly, meaning you can hit the gym again sooner to burn more calories. If you're not exercising, mix protein powder into water or milk for the occasional afternoon snack that will suppress your appetite and keep you away from your office mate's candy bowl or the vending machine.
Protein Powder Pitfalls
Protein powder could undermine weight loss if you mix it into a high-calorie shake or smoothie. Most powders have between 90 and 120 calories per serving. Add yogurt, juice, banana, honey and other fruit, and suddenly your sensible snack has more calories and sugar than some meals. Mix the drink into low-fat milk or water when you use it as a snack. If you're using protein powder as a meal replacement, add just 1/2 to 1 cup of fruit and 1/2 cup of milk. This helps to keep the calories in check.
Protein Powder Precautions
Avoid protein powders that contain extra carbohydrates, especially in the form of sugar. Natural flavorings, such as chocolate or berry, usually don't increase the protein powder's calorie content and make the powder more palatable. Be wary of protein powders that contain extra supplements, as these aren't well-regulated by the U.S. Food and Drug Administration.
Check with your doctor before adding protein powder to your diet if you're under medical supervision for a specific health condition or on medication that requires you to monitor your protein intake. For most people, barring any allergies to ingredients in a protein powder, a daily serving of protein powder is perfectly safe.
Some protein powders contain contaminants, as reported in Consumer Reports in 2010. An investigation of protein powders and premixed protein drinks found that most contained some heavy metals, such as arsenic, lead and mercury, which can have a toxic effect on the body's organs if consumed in large quantities.