Shakes have become a very popular way for people wanting to get fitter and trimmer to top on protein. So it would be an unhappy irony if you were to end up with a "protein belly" through drinking them too enthusiastically. To avoid weight gain from protein shakes you need to use them wisely.
Diets with plenty of protein appear to be linked with lower belly fat and may make it easier to control your weight. However, you could experience weight gain from protein shakes if drinking them means your overall calorie intake is too high for your needs.
Why Protein Is so Vital
The Centers for Disease Control and Prevention explains that there are 20 different amino acids that together make up the proteins we need for the structure of every cell, tissue and organ. Some of these can't be made by the human body, so they are known as essential amino acids — that is, it's essential that the diet provides them.
According to the Academy of Nutrition and Dietetics, any time your body is growing or repairing itself, protein is needed. The nutrient also helps:
- Fight infection
- Carry fats, vitamins, minerals and oxygen around the body
- Keep body fluids in balance
- Clot blood
The British Nutrition Foundation adds that protein tends to make people feel fuller than carbohydrates or fat. Getting plenty of the nutrient may therefore make it easier to control your calorie intake.
How much is the right amount? According to the Cleveland Clinic, adults require 0.8 grams of protein per kilogram of body weight (1 kilogram equals 2.2 pounds). However, very active people need more. Endurance athletes require 1.2 to 1.4 grams of protein per kilogram of body weight and strength athletes require 1.2 to 1.7 grams of protein per kilogram of body weight.
This means if you weigh 140 pounds (63.6 kg), you could need as little as 50 grams of protein if you aren't active, or as much as 108 grams if you pump a lot of iron.
Read more: How Much Protein Is Right for You?
Food Sources of Protein
The 2010-2015 Dietary Guidelines for Americans recommend that a healthy eating pattern should include a variety of protein foods, including seafood, lean meats and poultry, eggs, legumes (beans and peas), and nuts, seeds and soy products.
As a rough rule of thumb, 1 ounce of cooked lean animal source protein has around 7 grams of protein. According to USDA analysis, 3 ounces of stewed skinless chicken thigh has 20.3 grams of protein, 3 ounces of steamed or poached salmon provides 21.9 grams of protein and 3 ounces of cooked lean ground beef has 21.3 grams protein.
Plant sources of protein are generally overall lower in the nutrient, but also tend to be lower in saturated fat and sodium. Plus, they come along with other valuable components, such as fiber and antioxidants.
The Harvard T.H. Chan School of Public Health says it's this protein package — the different types and quantities of fats, fiber, sodium and more — that makes a difference for health.
For example, a sirloin steak is a great source of protein, but is also quite high in not-so-healthy saturated fat, whereas a protein-rich fatty fish is also an excellent source of healthy omega-3 fats most of us should be eating more of on a regular basis. Meanwhile, lentils pack a punch of protein and also contain lots of fiber and virtually no sodium or saturated fat.
The Role of Protein Shakes
In theory you should be able to get the protein you need from food, but protein shakes, such as those made from soy or whey, can be useful to get extra protein should you decide you need it. The Harvard T.H. Chan School of Public Health says a wide range of protein intake — anywhere from 10 to 35 percent of calories — is acceptable. You may want to be at the upper end of protein intake to help with your fitness and weight management goals.
According to the Cleveland Clinic, protein powders are a quick way to help ensure that your body is nourished and satisfied. The two main reasons to consider a protein shakes would be to:
- Recover after exercise: Your muscles are most responsive to the use of protein for the repair and growth process within 60 minutes of strenuous exercise.
- To control your weight: A steady supply of protein at each meal and as a snack will help keep you full. It's worth noting that weight gain from protein shakes isn't unheard of either, though.
Shakes and Belly Fat
A study involving overweight and obese patients in a 2018 issue of the Journal of the American College of Nutrition found a link between supplementing with dairy whey protein, which is commonly used in protein shakes, and improvements in body weight, total fat mass and some cardiovascular disease risk factors.
A diet rich in good quality protein could also directly benefit belly fat levels, according to research published in the January 2012 issue of Nutrition & Metabolism. In this study, higher intakes of protein replete in essential amino acids were associated with a lower percentage of fat in the central abdominal area.
Harvard Health Publishing say abdominal fat cells are the ones in the body that are biologically the most active, producing hormones and other substances that can significantly affect our health. Being apple shaped with a fat belly means you are likely to have higher total cholesterol and LDL (bad) cholesterol, lower HDL (good) cholesterol and insulin resistance.
Ultimately though it's about calories. Protein contains 4 calories per gram — the same as carbohydrate — and could lead to weight gain, including belly fat, if you over consume it. The Mayo Clinic says if you drink protein shakes in addition to your usual meals and you're not exercising, you can actually make losing weight more difficult or even create a protein belly.
Protein Shake Cautions
To avoid a protein belly and the risk that protein could actually lead to weight gain rather than loss, the Cleveland Clinic says you should choose shakes with no added sugars or dextrins/maltodextrins (sweeteners made from starch). Also to avoid a gainer shake fat belly, don't choose those with added branched-chain amino acids (BCAAs), as these bulking up shakes may help promote too much muscle growth and, potentially, weight gain.
You should also take care with protein powders if you have any kidney issues, with the Cleveland Clinic advising that people with kidney disease should choose protein powders that have a lower range protein content (10 to 15 grams per serving). This is because compromised kidneys can't tolerate a lot of protein at one time.
To avoid gastrointestinal problems, people with irritable bowel syndrome or lactose intolerance should choose powders that don't contain lactose sugars, artificial sweeteners or dextrins/maltodextrins. And if you have a gluten allergy or sensitivity, you need to look for powders that don't contain gluten.
- Centers for Disease Control and Prevention: "Protein"
- Academy of Nutrition and Dietetics: "How Much Protein Should I Eat?"
- British Nutrition Foundation: "Protein"
- Cleveland Clinic: "What You Need to Know About Protein"
- Health.gov:"Dietary Guidelines for Americans, 2015-2020"
- USDA FoodData Central: "Chicken, Thigh, Stewed, Skin Not Eaten"
- USDA FoodData Central: "Salmon, Steamed or Poached"
- USDA FoodData Central: "Ground Beef, 90% - 94% Lean, Cooked"
- Harvard T.H. Chan School of Public Health: "Protein"
- Cleveland Clinic: "7 Tips for Choosing the Best Protein Powder for You"
- Journal of the American College of Nutrition: "Whey Protein Supplementation Improves Body Composition and Cardiovascular Risk Factors in Overweight and Obese Patients: A Systematic Review and Meta-Analysis"
- Nutrition & Metabolism: "Quality Protein Intake Is Inversely Related With Abdominal Fat"
- Harvard Health Publishing: "Abdominal Fat and What to Do About It"
- USDA National Agricultural Library: "How Many Calories Are in One Gram of Fat, Carbohydrate, or Protein?"
- Mayo Clinic: "I'm Trying to Lose Weight. Could Protein Shakes Help?"