Can Eating Too Much Protein Harm Your Health?

Any food can be sold with the dream line: ‘high in protein’. You won’t really hear that protein is the ‘bad guy’ when advertising food. Also, there are popular weight loss diets based on high protein intake. Are these safe actually? What happens if you eat too much protein? What are the potential side effects? Animal protein vs plant protein – what’s the truth?

What is the first food you can think of when you hear the word ‘protein’?
Is it meat? Or maybe eggs, fish? Yes, most people think about these when it comes to protein. That’s what we were all told during the last decades.
What is protein?
I won’t start now any chemical explanation. Let’s just say protein is one of the nutrients we need higher quantities of (that is why it is called macronutrient , together with the carbohydrate, dietary fat and water). 
Protein is made up of amino acids – these are the building blocks. Our body actually needs the amino acids, not the protein. Basically our body breaks down what we eat and then builds the protein which can be found in every single cell in the human body. So it is extremely important to make sure our body has enough protein, in other words that we are getting enough amino acids.
There are altogether 20 amino acids, and the important data is that there are 9 out of these  20, which our body cannot make itself, so we need to get these 9 amino acids from our food. 
Why meat, fish and eggs are considered more valuable protein than plant foods?
Few decades ago there was a propaganda started about ‘complete’ and ‘incomplete’ protein. (Nowadays these terms are not officially used by nutritionists any more).
So called ‘complete’ protein meant that the protein in the food contained all of the 9 essential amino acids in high quantities (this is true for meat, fish, eggs).
And then the plant based foods were named (wrongly) incomplete protein, even if they contained all of the essential amino acids too. The reason was that most of the plant foods had one of the amino acids in lower quantities than the other 8. 
This propaganda still has its effects. Most people ask vegetarians and vegans surprised about where they get their protein from.
Do vegans and vegetarians get enough protein from their diet?
First of all: what’s the difference between vegans and vegetarians? Vegetarians don’t eat meat or fish, but they still eat dairy, eggs, etc. Vegans on the other hand don’t eat any animal-related food, so no eggs, no dairy, only plant foods.
In general, eating a varied plant based diet will provide all the amino acids in adequate quantities. What happens is that let’s say one is low in one of the amino acids, but that amino acid is abundant in the other, so basically overall the body gets everything it needs.
Is there any danger of not getting enough protein? Who is in danger?
In general the answer is: No. The bigger problem is getting too much protein, mainly animal protein.
The only case when inadequate amount of protein is taken is a very low calorie diet, or fruit based diet, or any kind of diet which contains refined sugars, white bread, white pasta in high quantities and less whole food. 
Attention must be paid if you recognize any of the above as being your diet, because once the body does not get enough amino acids to build the protein needed, it will start getting it from the muscles, organs, etc.
What’s wrong with the animal protein? Is there any danger getting too much of it?
Eating animal protein is indeed an ‘easy’ way to get high amount of essential amino acids.  
One of the problems – and maybe the biggest one – is that getting the protein mainly from animal food will naturally lead to not having an appetite for veggies, beans, nuts, etc. So your body will miss out many essential nutrients found only in plant foods. 
If you feel yourself not being a fan of veggies, look at your diet, and see if there was too much meat in it. 
In general, getting your protein mainly from animal food leads easily to get too much protein. 
Is eating too much protein bad?

Eating too much protein puts stress on kidneys, as kidneys have to work really hard when processing protein.
Too much protein may lead to osteoporosis (a condition where bones become fragile because of loss of tissue). This can happen because while the body processes the protein, the kidney will excrete more calcium. When there is not enough calcium in the body, the body automatically uses the stored calcium from bones. So too much protein leads to less calcium in the body and thus potential risk of osteoporosis.
While on a high protein diet, the skin, the eyes can get very dry, as processing protein requires plenty of water in the body.
Bad breath is another side effect of eating too much protein.
Can too much protein lead to body fat gain?

Yes, of course. The same way as carbohydrates and dietary fat, the amount of protein which will not be used as energy or to repair muscles, will be stored by the body in the form of fat. 
Obviously when starting a weight loss diet based on high amount of protein and cutting out the carbohydrate, will lead to weight loss in the short term. But it is an unsafe way of losing weight. Beside the side effects listed above, avoiding carbohydrates fully has its own negative effects on the body too. (About carbohydrates in another article).
What’s the conclusion?
1. Don’t worry about the protein if you  don’t feel like eating meat every day. If you eat lots of veggies, legumes, whole grains, nuts, your body gets plenty of protein. And don’t worry about going vegan! (The author of this article is vegan, having much more energy than before, while eating meat).
There are many famous athletes (even body builders – would you believe? ) following a vegan diet. (Check out
2. Protein is not THE good guy. Our body needs everything, ALL the macronutrients (protein, carbohydrate, fat, water), plus vitamins and minerals. Cutting out any of these will lead to countless of health problems in the long run.
3. Be very careful with the popular and advertised weight loss diets based on high protein intake. Do your own research, and find out what the risks are. My suggestion is not to start any of these diets. They do more harm than good. Those lost pounds are just not worth it, if you end up with dry skin, bad breath, osteoporosis and so forth. And besides, those pounds will come back anyway when you follow such a diet.
This article supposed to be short… Well, there would be much more to say about the topic. If you have any questions, contact Lily:
While paying attention to what you eat, don’t forget to add regular exercise to your lifestyle. Why not try out one of our ZUMBA fitness classes in Dublin 2, Dublin 6 or Dublin 8. CLICK HERE for locations, maps and prices.