Can You Eat Too Much Protein?
Welcome back to Blasphemous Nutrition! I am your host Aimee, talking with you today about protein and helping you determine what’s at steak if your protein intake is high and what is whey overblown!
Protein is probably the most talked about macronutrient in the past couple of years, and it is about time! Celebrated as a cornerstone of muscle building and metabolic health, it’s also been targeted as a cause of kidney damage and gout. Old myths about protein have resurfaced into the spotlight, and some of these concerns have merit while others are long proven false. So, what’s the real story? Can you overdo it with protein? In this podcast, I’ll dive deep into the effects of high protein intake on body composition, debunk myths about kidney health, clear up some confusion around gout and explore how to make sure you get the right amount of this potent macronutrient.
The Role of Protein in Body Composition
Muscle Growth and Maintenance
Protein is the building block of muscle, and its importance in this role, as well as immune health, becomes even more pronounced as we age. For women over 40 and men over 50, maintaining muscle mass is crucial for staying active, resilient, and strong into our senior years. Protein provides the amino acids needed to repair and grow muscle tissue, especially after exercise or injury and ensures we maintain a robust immune system.
When combined with strength training, increasing your protein intake can:
Boost muscle protein synthesis, the process by which muscles repair and grow.
Counteract the muscle loss (sarcopenia) that occurs with age and hormonal changes.
Enhance recovery after workouts, reducing soreness and improving performance over time.
Research, and my own clinical experience has shown that even in overweight, sedentary adults, increasing protein can increase muscle mass, even without activity! (1) I interpret this as evidence that for many, current protein intake falls short of what the body requires to maintain optimal muscle mass.
Impact on Body Fat
One of the most remarkable benefits of protein is its ability to support fat loss without sacrificing muscle. Here’s how it works:
Increased Satiety: Protein is the most satiating macronutrient, meaning it helps you feel full longer and reduces the temptation to overeat.
Thermic Effect: Protein digestion burns more calories than carbohydrates or fat, giving your metabolism a slight boost. Gram per gram, protein can burn 20-25% more calories in the process of digestion than fats or carbohydrates!
Blood Sugar Stability: By slowing carbohydrate absorption, protein helps stabilize blood sugar levels, reducing cravings and energy crashes, thus helping you stay active and avoid foods which sabotage your progress.
Studies often show that higher-protein diets can lead to better weight management and improved body composition, especially when paired with physical activity. For example, research published in the Journal of the International Society of Sports Nutrition examined the effects of 16 weeks of two different higher-protein diets combined physical activity in men who had already been weight training. The study concluded that high-protein diets of either 1.6g/kg or even 3.2g/kg (this translates to 109-217 grams of protein daily for 150 pound active male) alongside structured exercise, significantly improved body composition in this population without adverse effects on liver and kidney function.
Debunking the Kidney Myth
The Myth: High-Protein Diets Cause Kidney Damage
You’ve probably heard the claim that eating too much protein can harm your kidneys. This idea originated from research on individuals with pre-existing kidney disease, where limiting protein intake is often recommended to reduce strain on compromised kidneys. However, this doesn’t apply to people with healthy kidneys.
The Truth: No Evidence of Harm in Healthy Individuals
Decades of research have shown that high-protein diets do not impair kidney function in healthy people. Your kidneys are designed to handle the metabolic byproducts of protein digestion, such as urea, without issue. In fact:
Healthy Kidneys Adapt: When protein intake increases, kidneys adjust by temporarily increasing their filtration rate—a natural and harmless response. Sometimes this shows up in labs as elevated kidney markers, but it is nearly always a temporary aberration as the body adjusts and not at all indicative on damage occurring.
Scientific Consensus: Multiple studies, including long-term trials, have found no evidence that high-protein diets damage kidney function in healthy adults. A systematic review and meta-analysis published in The Journal of Nutrition found that changes in kidney function do not differ between healthy adults consuming higher- compared with lower- or normal-protein diets. This comprehensive analysis supports the safety of high-protein diets in individuals without pre-existing kidney conditions.
When to Be Cautious
For individuals with advanced kidney disease, managing protein intake is essential to avoid overloading already compromised kidneys. However, for the vast majority of people, protein poses no risk to kidney health. Long-term studies have confirmed that high-protein diets do not impair kidney function in healthy individuals. Meta-analyses have shown no significant differences in renal biomarkers between individuals consuming low versus high-protein diets.
Protein Intake and Gout
Gout, a form of arthritis caused by elevated uric acid levels, is another concern often linked to protein. Here’s the thing though - not all proteins are problematic, foods high in purines—substances that break down into uric acid—can exacerbate gout symptoms. Proteins rich in purines include red meat, turkey, organ meats, and certain seafood.
Research from The Journal of Arthritis Care & Research indicates that dietary purines are a modifiable risk factor for gout but do not necessitate protein restriction in most individuals. Instead, low-purine options like dairy, chicken, duck, oysters, and plant-based proteins offer effective alternatives without compromising nutritional needs. It’s also important to note that sugar, high fructose corn syrup, and alcohol are as bad or worse than most protein foods when it comes to exacerbating gout, and provide no nutritional benefit. I’ve seen some patients improve gout by eliminating these foods first and reducing frequency of high purine foods but not needing to be strict about purines when other aspects of the diet are addressed.
Balancing Protein Intake for Gout Management
Choose Low-Purine Proteins: Opt for protein sources lower in purines, such as dairy products, eggs, chicken, duck, oysters, crab, cod, salmon and plant-based proteins like legumes and tofu. These provide necessary nutrients without significantly increasing uric acid levels.
Moderation is Key: It’s not necessary to eliminate all high-purine foods. Moderate consumption, combined with other dietary adjustments, can help manage gout effectively.
Hydration: Staying well-hydrated supports kidney function and helps flush excess uric acid from the body.
While managing purines is essential for those with gout, a low-protein diet is not the solution. In fact, insufficient protein can lead to muscle loss, impaired immune function, and nutrient deficiencies—outcomes that can negatively impact overall health, especially if you also struggle with obesity and elevated blood sugar.
The Real Risk: Crowding Out Other Nutrients
While protein is a powerhouse nutrient, consuming it in excess can sometimes lead to an unintended consequence: pushing other vital nutrients off your plate. This isn’t about protein itself being harmful, but rather about maintaining a balanced diet.
Why Balance Matters
A high-protein diet that crowds out fruits, vegetables, and other plant foods can leave you short on:
Fiber: Essential for digestion, blood sugar control, and heart health.
Antioxidants: Found in colorful produce, these compounds combat oxidative stress and inflammation.
Micronutrients: Vitamins and minerals like vitamin C, potassium, and magnesium are abundant in plant-based foods but scarce in protein-rich animal products.
Tips for Maintaining Balance
Protein and Produce at Every Meal: Make sure your plate includes plenty of non-starchy vegetables alongside your protein source.
Focus on Variety: Rotate between different protein sources (e.g., chicken, fish, lentils, eggs) to keep meals interesting and nutrient-dense.
Snack Smart: Pair protein with a serving of fruit or raw veggies to get the best of both worlds.
Signs of Excess Protein
While most people are far below the upper limit for protein intake, consuming excessive amounts can lead to:
Digestive Discomfort: Issues like bloating or constipation, especially if fiber intake is low.
Dehydration: Protein metabolism requires more water, so staying hydrated is essential. Signs of dehydration like headaches, muscle cramps, fatigue and concentrated urine are signs and symptoms to look for.
Lack of Food Variety: A hyper-focus on protein can crowd out other nutrient-rich foods.
How Much Protein Is Too Much?
A Closer Look at Protein Requirements
The US RDA for protein (0.8 g/kg/day) represents the minimum intake to prevent malnutrition, not the ideal for health. This figure was derived from older nitrogen balance studies that underestimate needs by allowing the body to adapt to low protein levels at the expense of optimal processes like immune function and protein turnover.
Protein, but not fats nor carbohydrates, contain nitrogen. Early protein studies used what is called nitrogen balance to assess adequate protein. A nitrogen balance study is a method used to measure protein requirements by comparing nitrogen intake (from dietary protein) to nitrogen excretion (primarily through urine and feces). The goal is to determine whether the body is in:
Positive Nitrogen Balance: More nitrogen is retained than excreted, indicating protein synthesis exceeds breakdown—common during growth, pregnancy, or muscle building.
Negative Nitrogen Balance: More nitrogen is excreted than retained, suggesting muscle or tissue breakdown—common during illness, injury, or inadequate protein intake.
Equilibrium: Nitrogen intake matches excretion, meaning the body maintains its current protein levels.
This method has limitations as it requires participants to consume experimental diets for weeks, allowing the body to adapt to low protein levels by reducing non-essential functions, like protein turnover, rather than measuring optimal protein needs for health and performance.
When the body is in a deficit, it will utilize what it can get to prioritize essential needs over long-term needs. In the case of what we initially saw with nitrogen balance studies, as the body adapted to a low protein diet, readings showed balance was achieved when the body was actually adjusting to low intake and reaching an equilibrium by dialing down immune function and cell turnover.
Modern methods like the Indicator Amino Acid Oxidation (IAAO) technique suggest higher intakes are more appropriate. Research using IAAO estimates that 1.2 g/kg/day better supports muscle health, immune function, and overall vitality for both younger and older adults. Adjusting your intake to this level can significantly enhance long-term health, whether or not you are physically active.
Based on findings from Examine.com, here are protein recommendations:
Sedentary Adults: 1.0 to 1.2 grams per kilogram of body weight per day.
Physically Active Individuals: 1.2 to 2.0 grams per kilogram of body weight per day, tailored to exercise intensity.
Athletes or Those Seeking Muscle Gain: Up to 2.2 grams per kilogram of body weight per day may be beneficial.
Elderly Individuals: 1.2 to 2.0 grams per kilogram of body weight per day to counteract sarcopenia and maintain mobility.
For a 150-pound (68-kg) individual, based upon age and activity level this translates to:
Sedentary: 68 - 85 grams/day
Active: ~80-135 grams of protein per day.
Athletes: Up to 150 grams daily - effectively 1 gram per pound of body weight.
Older Adults: ~80-135 grams of protein per day.
Practical Strategies for a Balanced High-Protein Diet
Incorporate Protein Mindfully
Getting enough protein on your plate doesn’t have to be complicated. Here are some ideas:
Breakfast: Greek yogurt with berries and a handful of nuts.
Lunch: Grilled chicken salad with mixed greens, avocado, and a side of quinoa.
Dinner: Salmon with roasted Brussels sprouts and sweet potato.
Snacks: Hummus with sliced bell peppers or a boiled egg with an apple.
Emphasize Variety
Animal-Based Proteins: Include a variety of meats, eggs, and dairy, as well as fatty fish like salmon, sardines or mackerel for heart-healthy omega-3s and a variety of vitamins and minerals.
Plant-Based Proteins: Incorporate lentils, chickpeas, tofu, tempeh and edamame to boost fiber and get additional micronutrients.
Stay in Tune with Your Body
Your body’s cravings and energy levels are good indicators of whether you’re getting the right amount of protein. Adjust your intake based on your activity level, goals, and how you feel. If you’re curious about your ideal protein intake or need guidance tailoring your diet to your goals, reach out to a professional, like myself, for a personalized consultation. The link for a complimentary 15 min consult is in the resources below.
Conclusion
Protein is an essential ally in building and maintaining a vibrant, strong body, but as with everything, there can be too much of a good thing. It just isn’t where you’ve been told to look! Higher-protein diets are not only safe for most people but also beneficial for muscle growth, fat loss, and metabolic health. The real risk lies in neglecting the other nutrients your body needs to thrive if you focus exclusively on protein at the expense of other healthy foods.
By pairing protein with an abundance of vegetables, fruits and healthy fats, you can enjoy all the benefits of a diet rich in protein without compromising your overall nutrition.
Resources:
Tagawa, R., Watanabe, D., Ito, K., Ueda, K., Nakayama, K., Sanbongi, C., & Miyachi, M. (2020). Dose–response relationship between protein intake and muscle mass increase: a systematic review and meta-analysis of randomized controlled trials. Nutrition Reviews, 79, 66 - 75. https://doi.org/10.1093/nutrit/nuaa104.
Antonio, J., Ellerbroek, A., Silver, T., Vargas, L., Tamayo, A., Buehn, R., & Peacock, C. (2016). A High Protein Diet Has No Harmful Effects: A One-Year Crossover Study in Resistance-Trained Males. Journal of Nutrition and Metabolism, 2016. https://doi.org/10.1155/2016/9104792.
Bray GA, Smith SR, de Jonge L, Xie H, Rood J, Martin CK, Most M, Brock C, Mancuso S, Redman LM. Effect of dietary protein content on weight gain, energy expenditure, and body composition during overeating: a randomized controlled trial. JAMA. 2012 Jan 4;307(1):47-55. doi: 10.1001/jama.2011.1918. Erratum in: JAMA. 2012 Mar 14;307(10):1028. PMID: 22215165; PMCID: PMC3777747.
Bagheri R, Kargarfard M, Sadeghi R, Scott D, Camera DM. Effects of 16 weeks of two different high-protein diets with either resistance or concurrent training on body composition, muscular strength and performance, and markers of liver and kidney function in resistance-trained males. J Int Soc Sports Nutr. 2023 Dec;20(1):2236053. doi: 10.1080/15502783.2023.2236053. PMID: 37516903; PMCID: PMC10388821.
Larsen MS, Witard OC, Holm L, Scaife P, Hansen R, Smith K, Tipton KD, Mose M, Bengtsen MB, Lauritsen KM, Mikkelsen UR, Hansen M. Dose-Response of Myofibrillar Protein Synthesis To Ingested Whey Protein During Energy Restriction in Overweight Postmenopausal Women: A Randomized, Controlled Trial. J Nutr. 2023 Nov;153(11):3173-3184. doi: 10.1016/j.tjnut.2023.08.011. Epub 2023 Aug 19. PMID: 37598750.
Optimal Protein Intake Guide & Calculator. Examine.com. (n.d.). https://examine.com/guides/protein-intake/#aaaI-how-much-protein-do-you-need-per-day
Elango R, Humayun MA, Ball RO, Pencharz PB. Evidence that protein requirements have been significantly underestimated. Curr Opin Clin Nutr Metab Care. 2010 Jan;13(1):52-7. doi: 10.1097/MCO.0b013e328332f9b7. PMID: 19841581.
Share this post