High-protein, low-carb diets can cause some side effects. However, these side effects are usually related to more significant carb restriction.
For example, very low-carb diets like the keto diet can lead to symptoms22 like headaches, fatigue, constipation, and irritability. Cutting carbs too severely can also lead to low blood sugar. This is another reason why more moderate low-carb diets are better suited for most people.
In terms of protein, studies show that even extremely high-protein diets are generally safe and not associated with adverse side effects, even when followed for a long time period.
A 2016 study23 published in the Journal of Nutrition and Metabolism found that following a high-protein diet that provided between 2.51 to 3.32 grams per kg or 1.14 to 1.5 grams per pound per day for one year had no harmful effects on any measures of health in athletic men.
Another important thing to consider is protein sources. Diets high in certain types of animal proteins, like red and processed meats, have been associated with an increased risk24 of certain health conditions, like colon cancer.
Plus, there are environmental concerns25 with eating a diet super high in animal protein.
“It all comes down to how animal-based proteins are raised and prepared. If you’re consuming protein from farms that use regenerative agriculture, those are the protein sources that are most sustainable,” Cannon tells mindbodygreen. Here’s a comprehensive primer on how to eat meat more sustainably.
