A common belief is that a high-protein diet will facilitate an increase in muscle mass, strength, and function across the lifespan. However, is a high-protein diet still beneficial in the absence of any resistance-type exercise? Recent evidence from the world-leading laboratory of Professor Dudley Lamming at the University of Wisconsin-Madison has shown a high-protein diet, without any exercise, causes insulin resistance and an accumulation of white adipose tissue in as little as 18 weeks, even when matched for caloric intake. Here we discuss these provocative findings, their mechanisms, and how to prevent them.
- A high-protein diet without exercise can cause insulin resistance and an accumulation of white adipose tissue in as little as 18 weeks, even when matched for caloric intake.
- While higher-protein diets, when combined with resistance exercise training, may result in increases in muscle mass, the actual role of dietary protein in these adaptations is minimal.
- Kidney damage is a common myth associated with high-protein diets; systematic review & meta-analysis data suggest that dietary protein is not going to cause any damage to your kidneys, even when consumed long-term.
- Chronically elevated mTOR activation may cause anabolic resistance and contribute to sarcopenia; pharmacological therapies may be needed to restore mTOR activity to youthful levels.
- High-protein diets (>30% total energy intake) may impair glycaemic control during weight-loss interventions, even when caloric restriction is apparent and large reductions in fat mass (>10%) are observed. Certain amino acids, notably the overconsumption and elevated levels of the BCAA’s, Isoleucine, and Valine, may be partially responsible for these effects.
- The consumption of a high-protein diet in the absence of exercise may be causing some level of metabolic damage in the long term due to impaired insulin sensitivity, increased insulin-glucagon, and impaired suppression of hepatic glucose production. Exercise is important for preventing negative effects associated with high-protein diets.