Negative Side Effects of Chronically High-Protein Diets


For the purposes of this post, we're defining "high protein" as more than 35% of your total caloric intake. 

If you're new to the world of fitness, the amount of information out there about nutrition can be really overwhelming. Should you do vegan, should you do chicken/sweet potatoes/broccoli, should you go gluten free, should you track your macros, etc. It's a lot. And the research can sometimes point in multiple directions. Here at Sweat Stretch Eat, I base my guidance off of what I have learned through my NASM CPT training, my NAFC Nutrition Coach training, and from a lot of different books/research that I read. I'm trying to help you navigate the hype and do what's best for your body. 

Today, I want to talk about protein. 

The Recommended Dietary Allowance for protein is 0.4g/lb per day. For me, at 116lbs, that would mean my RDA is 46.4g of protein per day. For endurance and strength athletes, the recommendation is slightly higher -- 0.5-0.8g/lb for strength and 0.5-0.6g/lb for endurance. Since I'm training for a marathon currently, I'd consider myself an endurance athlete, so I'd want to be between 58-69g of protein a day. Even to me, that sounds really low, but I think that's because we've been brainwashed into thinking we need a crazy amount of protein each day in order to be fit/healthy. I generally keep mine around 20-25% of my overall intake.

I did some searching for dietary recommendations across the fitness community and here's what I found: 

Jamie Eason LiveFit Trainer Sample Day for Females

  • Calories: 1571
  • Protein: 228.6g (58% of overall caloric intake)
  • Carbs: 107.8g 
  • Fat: 35.7g

What?! 228.6g -- is that a joke? That's so much. That's even more than regular bodybuilder types recommend, which is typically 1.0g/lb or 1.2g/lb. For me, that would almost be 2g/lb!

Kayla Itsines HELP Nutrition Guide Sample Day

  • Calories: 1700
  • Protein: 96 (22% of overall caloric intake)
  • Carbs: 252
  • Fat: 34

Much more reasonable! Doing good, Kayla.

Tone It Up Nutrition Plan (Vegan Edition) Sample Day

  • Calories: 1317
  • Protein: 82 (25% of overall caloric intake)
  • Carbs: 134
  • Fat: 55

Well, that was pretty eye opening for me. Was it for you? Let's get back to talking protein overload. Studies show that high protein diets (above 35% of overall intake) can cause the following negative side effects:

  • High fat + low fiber (typical of high protein diets) are risk factors for heart disease and some types of cancer
  • Kidneys are required to work harder to eliminate extra uria created (really bad for people with kidney problems or a history of kidney stones)
  • Can increase urinary calcium losses and lead to decreased bone density
  • Can lead to dehydration because greater fluid consumption is required when eating large quantities of protein -- fun fact: protein requires approximately seven times the water for metabolism than carbs or fat
  • Low carb intake can lead to performance inhibition and low energy