Myth busted: Researchers show that a high-protein diet does not affect kidney function
A widely held and controversial myth that high-protein diets may cause kidney damage in healthy adults has been debunked by scientists at McMaster University, who examined more than two dozen studies involving hundreds of participants. The meta-analysis, published in The Journal of Nutrition, challenges the perceived dangers of a protein-rich diet, a notion first introduced in the 1980s which suggested processing large amounts of protein leads to a progressive decline in kidney function over time. “It’s a concept that’s been around for at least 50 years and you hear it all the time: higher protein diets cause kidney disease,” says Stuart Phillips, a professor of kinesiology at McMaster who oversaw the study. “The fact is, however, that there’s just no evidence to support this hypothesis in fact, the evidence shows the contrary is true: higher protein increases, not decreases, kidney function,” he says.
“Nutrient-rich, high-quality, protein-containing dairy foods in combination with exercise in aging persons to mitigate sarcopenia” by Stuart M. Phillips and Wendy Martinson
“Abstract Sarcopenic declines in muscle mass and function contribute to the risk of falls, reduced mobility, and progression to frailty in older persons. Mitigation of sarcopenia can be achieved by consumption of higher quality protein in sufficient quantities, which current research suggests are greater than the recommended intakes of approximately 0.8 g/kg bodyweight/d. In addition, higher levels of physical activity and participation in exercise to support cardiovascular fitness and musculoskeletal function work additively with protein in attenuating sarcopenia. This narrative review provides evidence to support a recommendation for per-meal protein targets in older persons that are underpinned by knowledge of muscle protein turnover. Based on work examining acute dose–responses of muscle protein synthesis (MPS) to protein, a proposed per-meal target for protein intakes is set at approximately 0.4–0.6 g protein/kg bodyweight/meal for older persons. Habitual patterns of dietary protein intake tend to emphasize a skewed protein distribution, which would not maximize muscle anabolism. Observational studies show that more even patterns of protein intake are associated with increased muscle mass and improved muscle function. A food-based approach to achieving these protein targets would be advantageous, and the nutrient density of the protein-containing foods would be particularly important for older persons. Dairy foods provide high-quality protein and contain several nutrients of concern for older persons. This brief review provides an overview of the science underpinning why dairy foods should be a point of nutritional emphasis for older persons. Practical suggestions are provided for implementation of dairy foods into dietary patterns to meet the protein and other nutrient targets for older persons.
“Abstract Compared to investigations on hypocaloric diets, the effects of chronic overfeeding have been less studied. It has been posited that consuming calories in excess of daily caloric requirements will result in a gain in body weight and in particular fat mass regardless of which macronutrient(s) are consumed. However, recent evidence suggests that there is a quantitative difference in protein versus carbohydrate and/or fat overfeeding as it relates to body composition. Protein overfeeding or the consumption of a high protein diet may not result in a gain in body weight or fat mass despite consuming calories that exceed one’s normal or habitual intake. Therefore, this review will provide an up-to-date narrative on the current scientific literature on various combinations of macronutrient overfeeding and its effects on body composition.
“In the present meta-analysis, no effect on markers of renal function was found after provision of a LowCarbDiet compared with a control diet in patients with type 2 diabetes.”
“The Effects Protein on Humans (Renal/Organ Health and Appetite).”
“Too much protein is bad for your organs”
TLDR; High Protein consumption doesn’t show organ damage, has high appetite reducing effect, and aids in weight loss (even with caloric surplus).
This claim came from a study in rats being fed high protein diets, so we’re already off to a shaky start. What happens when high protein is fed to humans?
The extra protein was consumed with whey protein powder, though subjects were free to consume whatever form of protein they liked.
No harmful effects on blood lipids, kidney, or liver function could be identified. Additionally, despite increases in total calorie intake, no subjects gained fat mass.
A 2005 study study concluded that 2g per kg in body weight had no harmful effects on the body and no current evidence showed harmful effects on renal health
This 2016 study has raised the bar even higher with 3g per kg, and still no damaging effects can be found.
For perspective, I weigh an average of 160lbs (72kg), so that would be an average of 216g of protein a day.
Formula:
(Body Weight in kg x Protein g = Daily Protein Goal)
(72kg x 3g =216g Protein)That’s a pretty hefty amount of food, most people barely manage to reach 1g/kg (unfortunately).
How much protein can one consume? There doesn’t seem to be a limit to how much protein one can consume that won’t eventually be absorbed
The practical takeaway is that protein is an extremely useful macro-nutrient, noted for its incredible effects on satiety with absence of weight gain, so great in fact, that it causes self imposed caloric deficits with no hunger in 15-30% protein diets.
Decreasing protein intake increases the amount of calories one consumes to compensate for lack of needed protein. (i.e. protein leverage hypothesis).
The reason I compiled all of these references is because I am tired of portions of the keto community being afraid of protein.
Even the tired old “too much protein results in blood sugar spikes = fat gain” has been carefully and thoroughly explained by researcher Amy Berger. This is a massive misunderstanding of how gluconeogenesis (GNG) works, which create glucose based on metabolic need, not inherent surplus of supply (i.e. large amount of protein). Protein intake as high as 2.2g per kg does not affect ketosis..
Protein is the most useful macro-nutrient, showing no damaging effects on organs and aids in weight loss via appetite reduction. Higher protein diets should be actively encouraged in a ketogenic diet for non-Type 1 diabetic/non-epileptic subjects.