From the Guidelines
Eating more protein does not necessarily make you more dehydrated, though it may slightly increase your fluid needs. When you consume protein, your kidneys need additional water to process and eliminate the nitrogen waste products that result from protein metabolism. This process requires adequate hydration to function efficiently, as noted in various studies on nutrition and hydration 1. However, this increased fluid need is modest and easily addressed by drinking water regularly throughout the day.
Key Considerations
- The average person should aim for about 8-10 cups (64-80 ounces) of fluid daily, with perhaps a slight increase when consuming high-protein diets.
- Older adults, in particular, have different hydration needs, with recommendations suggesting at least 1.6 l of drinks daily for older women and at least 2 l of drinks daily for older men 1.
- The protein itself in foods like meat, eggs, dairy, and legumes also contains water that contributes to your overall hydration status.
Hydration and Protein Intake
Most healthy individuals who maintain normal fluid intake will not experience dehydration simply from increasing their protein consumption. If you're increasing your protein intake significantly, simply be mindful of drinking water regularly, especially during and after exercise when fluid needs are already elevated. It's also important to consider the overall diet and ensure adequate intake of fluids from various sources, including water, milk, tea, coffee, and unsweetened fruit juice, as these all contribute to fluid intakes 1.
From the Research
Dehydration and Protein Intake
- The relationship between increased protein intake and hydration indexes was studied in a 12-week, randomized, crossover, controlled diet intervention study 2.
- The study found that fluid intake and fluid balance were unaffected by high protein intake, and the effect of increasing dietary protein on fluid status was minimal 2.
- However, blood urea nitrogen was higher for high protein vs low protein and vs moderate protein, and urine-specific gravity was higher for high protein vs moderate protein 2.
Kidney Health and Protein Intake
- High-protein diets may worsen renal function in individuals with impaired kidney function, and may also lead to de novo chronic kidney disease (CKD) 3.
- The quality of dietary protein may play a role in kidney health, with animal protein associated with an increased risk of end-stage kidney disease (ESKD) compared to plant-based protein 3.
- Potential mediators of kidney damage from animal protein include dietary acid load, phosphate content, gut microbiome dysbiosis, and resultant inflammation 3.
Fluid Balance and Dehydration
- There is no direct evidence to suggest that eating more protein makes you more dehydrated, but dehydration can occur due to various conditions and can be treated with intravenous fluid therapy 4, 5, 6.
- Accurate assessment of fluid status and careful definition of targets are needed to improve clinical outcomes in patients with acute kidney injury (AKI) or at risk of AKI 4, 5.
- A conservative strategy of fluid management may be effective in preventing AKI and improving clinical outcomes 4, 5.