High Protein Diet May Not Improve Insulin Sensitivity

By: Arlo Taylor

The use of protein to increase protein synthesis and decrease hunger is commonly used among many people, especially strength athletes. Protein does help prevent muscle loss and promote weight loss but according to certain studies, there is an effect in high protein intake that may do the opposite of what many people believe to do. A study in Washington University School of Medicine in St. Louis found that eating too much protein has a negative effect on insulin sensitivity. This is not good for diabetes risk!

This study tested 34 post-menopausal women with obesity (a risk factor for diabetes) for their insulin sensitivity levels. The scientists found that women who lost weight on a high protein diet had no changes in their insulin sensitivity while women who had less protein had a significant improvement in insulin sensitivity. In many overweight/obese people, their insulin does not properly manage blood sugar levels resulting is diabetes.1

The reason this happens is not 100% clear but the same results were found in another study done by Gordon Smith, et al. A high protein diet had a larger decline in lean tissue mass but did not have a positive change in metabolic functions. In a lower protein diet, a positive effect on muscle insulin sensitivity was seen which is very important for men and women who are at risk of type II diabetes.


In a healthy individual, this may not be as important but as a clinical dietitian, it shows that a focus on macronutrient composition for patient weight loss is important. The positive effect on insulin sensitivity for overweight/obese patients is just as important as the weight loss. Again, the mechanism for the lack of improvement of insulin sensitivity in a high protein diet is not clear but the results show that being aware of macronutrient composition is necessary for weight loss patients.2

In a normal individual, this may not affect them but for overweight and obese individuals, this can significantly improve their health. As a future dietitian, it is important to understand that there will be all kinds of patients with different diseases and disorders. Using different ratios of macronutrients can be a helpful tool to positively change certain metabolic functions.


  1. Washington University in St. Louis. High-protein diet curbs metabolic benefits of weight loss. https://www.sciencedaily.com/releases/2016/10/161011130002.htm. Accessed December 15th, 2016.
  2. Gordon I. Smith, Jun Yoshino, Shannon C. Kelly, Dominic N. Reeds, Adewole Okunade, Bruce W. Patterson, Samuel Klein, Bettina Mittendorfer. High-Protein Intake during Weight Loss Therapy Eliminates the Weight-Loss-Induced Improvement in Insulin Action in Obese Postmenopausal Women. Cell Reports. Volume 17, Issue 3, p 849 – 861.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s