From the Guidelines
Weightlifters who consume excessive protein are at risk of imposing significant health risks, including increased urinary calcium loss, potential facilitation of osteoporosis, and elevated risk of gout and diabetic renal disease. The risks associated with excess protein consumption in weightlifters are multifaceted, affecting various aspects of health. According to 1, a diet rich in animal protein can raise low-density lipoprotein (LDL) cholesterol levels, potentially increasing cardiovascular risk. Furthermore, high-protein foods are often high in purines, which can increase uric acid levels and cause gout in susceptible individuals.
Some key risks to consider include:
- Increased urinary calcium loss, potentially facilitating osteoporosis
- Elevated risk of gout due to high purine intake
- Potential acceleration of diabetic renal disease in individuals with diabetes
- Increased risk of cancer due to the elimination or restriction of essential nutrients like fruit, vegetables, beans, and whole grains
- Deficiencies in essential vitamins, minerals, and fiber due to restricted food choices
It is essential for weightlifters to be aware of these risks and strive for a balanced diet that meets their protein needs without exceeding them. A moderate protein intake, spread throughout the day, can help mitigate these risks while supporting muscle growth and overall health. As noted in 1, severely restricting carbohydrates can lead to fatigue, and it is crucial to maintain a balanced intake of carbohydrates, healthy fats, and micronutrients to support optimal performance and well-being.
From the Research
Risks Associated with Excess Protein Intake
- Excess protein and amino acid intake have been recognized as hazardous potential implications for kidney function, leading to progressive impairment of this organ 2
- High protein intake may cause glomerular hyperfiltration, a potentially maladaptive response, which may accelerate the progression of kidney disease 3
- Adverse effects associated with long-term high protein/high meat intake in humans include:
- Disorders of bone and calcium homeostasis
- Disorders of renal function
- Increased cancer risk
- Disorders of liver function
- Precipitated progression of coronary artery disease 4
- High dietary protein intake can cause intraglomerular hypertension, which may result in kidney hyperfiltration, glomerular injury, and proteinuria 5
- The quality of dietary protein may also play a role in kidney health, with animal protein associated with an increased risk of end-stage kidney disease (ESKD) compared to protein from plant sources 5
Kidney Function and Protein Intake
- A study found that protein intake under 2.8 g/kg does not impair renal function in well-trained athletes 2
- Another study found that higher-protein diets do not adversely influence kidney function in healthy adults, as measured by glomerular filtration rate (GFR) 6
- However, a review of studies suggested that there is currently no reasonable scientific basis to recommend protein consumption above the current recommended dietary allowance (RDA) for healthy adults due to its potential disease risks 4