A diet high in protein is often promoted as part of a healthy lifestyle, with many diets encouraging consumers to reduce carbohydrates and fats in favor of protein to lose weight and gain lean muscle. But what are the true benefits and risks of a 140-gram protein diet? This article explores the science behind protein consumption, examining both the advantages and potential downsides of such a diet.
The Role of Protein in the Body
Protein is essential for life - it's a building block of every human cell and is involved in the vital biochemical functions of the human body. It's particularly important in growth, development, and tissue repair. A continual supply of amino acids through the protein we eat is crucial for cell and tissue growth.
Protein is found in your muscles, bones, skin, hair, and other parts of your body, according to the Harvard T.H. Chan School of Public Health. It helps fuel several chemical reactions in your body, including powering the hemoglobin that moves oxygen in your blood. So, consuming protein is good for you.
Defining a High-Protein Diet
Defining what’s considered “high protein” is tricky, according to Kris Sollid, R.D., senior director of nutrition communications at IFIC. Some protein recommendations are based on the percentage of calories in a diet that comes from protein, while others are based on body weight.
Adults should get at least 0.8 grams of protein for every kilogram of body weight each day-which equates to about 7 grams per 20 pounds of body weight. Consuming any amount over that recommendation would be considered a high-protein diet, according to Leah Silberman, R.D., a registered dietitian at Medical Offices of Manhattan.
Read also: Muscle-Building Diet
Here’s what a high-protein diet can look like:
- High Protein Based on Body Weight: One high-protein rule for the average person is 1.2 grams or more of protein per kilogram of body weight, Sollid says. If you do intense workouts and weight training, you could up your protein to 1.75 grams.
- If you opt for 1.75 grams of protein per kilogram of body weight a day, that would equal:
- About 125 grams per day for a 154-pound person
- About 160 grams per day for a 200-pound person
- If you opt for 1.75 grams of protein per kilogram of body weight a day, that would equal:
- High Protein Based on Percent of Calories: Protein intake can vary depending on your caloric needs, which are influenced by your age, size, fitness level, and other factors, Sollid says. Another way to increase protein is to make protein-rich foods a significant portion of your daily calories. For instance, Sollid says high protein could be defined as more than 22 percent of your total daily calories.
- Here are some examples:
- About 80 grams of protein per day for a 1,500-calorie diet
- Around 110 grams of protein per day for a 2,000-calorie diet
- Around 140 grams of protein per day for a 2,500-calorie diet
- Around 135 grams of protein per day for a 3,000-calorie diet
- Here are some examples:
Therefore, a 140-gram protein diet would generally be considered a high-protein diet, especially for individuals with lower caloric needs or those who are not highly active.
Potential Benefits of a High-Protein Diet
A high-protein diet offers several potential benefits:
Weight Loss and Management
Protein has been shown to help with weight loss and weight management because it makes you feel full for longer. One study found that when overweight women increased their protein intake from 15 percent to 30 percent, they ate about 400 fewer calories a day. It's great for individuals striving to lose weight, as eating a diet with above FDA-recommended protein intake has been seen to increase loss of fat mass and decrease loss of muscle mass.
Muscle Building and Strength
Research also shows that eating more protein helps you maintain muscle mass and build muscles and strength during strength training. It's vital to muscle building.
Read also: Risks of a 100-Gram Protein Diet
Metabolism Boost
Protein has potential metabolism-boosting effects.
Blood Pressure and Bone Health
It could also help lower your blood pressure and promotes bone health.
Potential Risks and Downsides of a High-Protein Diet
While a high-protein diet can be beneficial, it also carries potential risks:
Kidney Strain
Excessive protein intake long term can strain your kidneys, especially if you’re at risk for kidney problems, Silberman says. High dietary protein intake can cause intraglomerular hypertension, which may result in kidney hyperfiltration, glomerular injury, and proteinuria.
Nutrient Imbalance
Focusing too much on protein could mean you’re neglecting other important nutrients, like fiber, Sollid says. Fiber is only found in plant foods, so depending on the source of protein, a high-protein diet that overly emphasizes animal foods and doesn’t include enough fruits, vegetables, and whole grains could also be a low-fiber diet.
Read also: Risks of 150g Protein Intake
Dehydration
Be sure to drink more water if you’re upping your protein, she adds, “It can lead to an increased risk of dehydration, as the body requires more water to metabolize and eliminate the byproducts of protein breakdown.”
Cardiovascular Risk
The researchers found that consuming more than 22 percent of daily calories from protein carries more downside risk than dietary benefit. An amino acid found in animal-protein foods, such as beef, eggs and milk, was found to be responsible for signaling activity in macrophage cells that typically clear away debris in blood vessels. As consumption of dietary protein increases, so does the consumption of leucine, the specific amino acid responsible for triggering this macrophage cellular activity in the blood. When functioning normally these macrophage cells work to keep blood vessels free from plaque buildup. When their production becomes overactive the resulting accumulation of spent cells in the vascular system can cause the plaque buildup and blockages they are supposed to prevent.
Bone Health Concerns
Diet which is high in protein generates a large amount of acid in body fluids. The kidneys respond to this dietary acid challenge with net acid excretion, and, concurrently, the skeleton supplies buffer by active resorption of bone resulting in excessive calcium loss. Moreover, acid loading directly inhibits renal calcium reabsorption leading to hypercalciuria in combination with the exorbitant bone loss.
Increased Cancer Risk
Up to 80% of breast, bowel, and prostate cancers are attributed to dietary practices, and international comparisons show positive associations with high meat diet. The association, however, seems to have been more consistently found for red meat or processed meat and colorectal cancer.
Disorders of Liver Function
High-protein/high meat diet could cause disorders of liver function and precipitate progression of coronary artery disease.
Potential Adverse Effects of Long-Term High Protein/High Meat Intake
The adverse effects associated with long-term high protein/high meat intake in humans were (a) disorders of bone and calcium homeostasis, (b) disorders of renal function, (c) increased cancer risk, (d) disorders of liver function, and (e) precipitated progression of coronary artery disease.
Protein Sources and Dietary Choices
Protein can come from a variety of plant and animal sources-what you choose to eat is a personal preference. Lean meat and poultry, fish, eggs, and dairy products are good animal sources. Beans, nuts, seeds, and soy products offer plant-based protein.
Animal Protein vs. Plant Protein
Compared with protein from plant sources, animal protein has been associated with an increased risk of ESKD in several observational studies, including the Singapore Chinese Health Study. Potential mediators of kidney damage from animal protein include dietary acid load, phosphate content, gut microbiome dysbiosis, and resultant inflammation. Animal foods provide predominantly acid precursors, whereas protein in vegetable foods is accompanied by base precursors not found in animal foods.
Choosing Lean Proteins
Choose lean meats and dairy for your proteins. Nothing says protein like a nice, juicy steak. And if you choose a lean cut, you will get all of the protein with far less unhealthy fat. In fact, a lean cut of beef like a top round steak has barely more saturated fat than a similar-sized skinless chicken breast.
Poultry Tips
If you choose white meat when you're buying chicken or other poultry, you’ll get a lot less fat than if you eat dark meat. Also, remove the skin, which has saturated fat.
Pork Options
Pork offers plenty of protein without too much fat, if you know what type to buy. Look for tenderloin, top loin, rib chops, sirloin steak, or shoulder blade steaks. Pork cuts are much leaner than they were decades ago.
Fish for Healthy Fats
Fish is loaded with protein and almost always low in fat. Even the fish that have more fat, such as salmon and tuna, are good choices. Those fish generally have omega-3 fatty acids, which are good for your heart. Most people don't get enough omega-3s.
Eggs for Low-Cost Protein
Eggs are a good source of lean protein. And even though there is cholesterol in the yolk, it is not as likely to raise your cholesterol level as foods that contain saturated fats and trans fats do.
Soy as a Plant-Based Option
Protein doesn't come only from animals. Tofu, soy burgers, and other soy-based foods are plant-based sources of protein. Bonus: Eating 25 grams of soy protein daily may help lower cholesterol.
Beans for Protein and Fiber
One and a quarter cup of beans has about as much protein as 3 ounces of broiled steak. Along with protein, the fiber in beans helps you feel full longer and also helps lower your LDL ("bad") cholesterol.
Dairy for Calcium and Protein
Milk, cheese, and yogurt give you protein and calcium for strong bones and a healthy heart. Low-fat, nonfat, or reduced-fat dairy products can help you keep calorie counts down.
Whole Grains for Fiber and Nutrients
Most high-protein diets limit grains, so make sure the grains you do eat are pulling their weight. Favor whole grains. You'll get fiber and nutrients. If you're buying products made with whole grains, check the labels to make sure they're not high in sugar or fat.
Fruits and Veggies
Most low-carb diets still include some vegetables but often limit fruit. There's no known harm to cutting out fruit temporarily to keep your carb count down.
Tips for Increasing Protein Intake
Working more of these foods into your meals and snacks will help you increase your protein intake.
Start with Protein at Breakfast
It will be remarkably harder to hit your protein goals if you do not consume any until lunch or later. Try adding high-protein Greek yogurt or a serving of nuts to your breakfast or as a mid-morning snack, Wells Sutton suggests. Because protein leads to increased satiety, this can also help curb snacking and cravings later in the day.
Diversify Protein Choices
Even if you aren’t looking to consume more protein, think about diversifying your protein choices to include more beans, chickpeas, lentils, peas, seafood, and soy foods.
Choose Carbohydrate Foods with Extra Protein
Yes, you can choose more carbs as you increase your protein intake. This is especially important for vegetarians or vegans, who will have a more limited list of protein foods accessible. For example, choosing quinoa or lentils instead of rice-or doing a mix of beans and rice. Even small changes can add up over time.
Consider Protein Powders
Prioritize whole foods, but do not be afraid to add in a high-quality protein powder to your routine. For individuals who are trying to build muscle, it can be very hard to eat enough protein. In such cases, a protein powder can help make the difference between muscle gain and plate. Either add protein powder to a nutrient-dense smoothie with fruits and veggies or try making a protein coffee.
Individual Protein Needs
The amount of protein your body needs depends on many factors, including your weight, age, body composition goals, physical activity level, and overall health.
The Recommended Dietary Allowance (RDA) for protein is 0.36 grams of protein per pound (0.8 grams per kg) of body weight. Some experts argue that physically active individuals need much higher amounts of protein than the RDA. Many professional organizations recommend 0.54-0.9 grams of protein per pound (1.2-2 grams per kg) per day.
For athletes, needs may be even higher. Additionally, pregnant and breastfeeding people, older adults, and those with certain medical conditions have higher protein needs than the general population.
Potential Complications and Considerations
Kidney Disease
For patients with CKD or at risk of CKD, high intake of dietary protein, including animal protein, may have detrimental effects on kidney function and long-term kidney health. High-protein diets should be avoided, if possible, and plant-based proteins may be recommended. In general, people with one kidney should avoid excessively high dietary protein intake (>1.2 g/kg per day) and high dietary sodium intake; they should also consume adequate dietary fiber and avoid obesity, maintaining a body mass index of <30 kg/m2.
The Ketogenic Diet
Although the ketogenic diet has recently received a disproportionate amount of attention because it is purported to help treat obesity and type 2 diabetes, evidence that it actually offers such benefits is limited. For patients with existing kidney disease, the diet’s high protein intake may accelerate the progression of their kidney disease.
The Importance of Fiber
The obsession with protein is distracting from what people are really deficient in: fiber. The Dietary Guidelines for Americans recommend that women eat 22 to 28 grams of fiber per day, while men should aim for 28 to 34 grams of fiber per day. Fiber is so important for regularity, gut health, heart health-because it can help to reduce cholesterol-[and] satiety.
To ensure you’re eating enough fiber, Amati recommends focusing on plants like fruits, vegetables, nuts, and seeds, and whole grains. Fill half your plate with some plant source-a salad, broccoli, sautéed zucchini.