You Asked: Can You Really Eat Too Much Protein?

By , SparkPeople Blogger
For a healthy adult, eating more protein than your recommended daily range once a week or so won't have any major impact on your long-term health or weight loss (assuming you still eat approximately the same amount of calories for the day). Based on your food selections for that day, if you consume a larger-than-normal amount of protein you may notice:
  • A change in bowel habits in the next 24-48 hours (due to a lower fiber intake)
  • A sluggish or light-headed feeling (if you also ate very few carbs)
  • Some abdominal discomfort if your fat intake sky-rocketed
  • No noticeable changes at all
However, you may be wondering how a long-term high-protein diet affects your health in the long run...
Honestly, nutrition experts don’t really know for sure because the research in the area of “high protein intake” is very limited. Throughout history, there have been populations who flourished by eating a predominately high-protein (high meat) diet.  It is estimated that the Eskimo Inuit had a diet composted of approximately 45% protein with fat making up the other 55%.  During the winter season, explorers on land would survive for months on a high meat diet.  However, a high-protein diet that is extremely low in fat will result in death after several weeks.  This condition is known as “rabbit starvation” for rabbit meat is an extremely low fat meat. 
While there is currently very little research regarding disease risks associated with a high protein diet, researchers do notice a correlation between long-term high-protein intake and diseases such as osteoporosis, renal stones, kidney disease, cancer, heart disease and obesity.  In fact, a 2014 study published in Cell Metabolism reported that middle-aged adults following a high-protein diet had a 75% increase in mortality, a four-fold increase in cancer and a five-fold increase in diabetes. 

However, these associations were decreased if the protein came from plants rather than animals.  This study also looked at older adults and found the reverse.  After age 65, a moderate- to high-protein intake actually decreased cancer risk and overall mortality. Yes, the "facts" we have about protein—what is too much and for whom—can be a little confusing.

So you may be asking, “How did SparkPeople come up with its recommended protein range for me?” 

SparkPeople wants to help all adults reach optimal health and well-being for a lifetime.  We therefore use the macronutrient distribution ranges that have been established by the Food and Nutrition Board of the Institute of Medicine, The National Academies.  This board of nutrition experts obtains the published research, analyzes all the studies, and then develops nutrition guidelines for use by organizations and health care professionals.  (For the complete report, click here. The protein information can be found in chapters 10 and 11.)

As already stated earlier, there is not a great deal of research regarding an upper limit for safety regarding protein intake.  So the Food and Nutrition Board first established ranges for fat and carbohydrate (of which there is a great deal more research), based on how these nutrients impact overall health and diseases such as heart disease, cancer, diabetes, and obesity.  Then to ensure a nutritionally adequate diet, the protein range was established to balance out the fat and carbohydrate. This protein amount easily meets the amino acid needs of the body, maintains muscle mass, and promotes satiety.

The end result for the macronutrient ranges for healthy adults:
  • Carbohydrates should make up 45-65% of total calories
  • Fat should make up 20-35% of total calories
  • Protein should provide 10-35% of total calories. To determine how much you need, read this detailed article.
This distribution of calories promotes life-long, optimal health and well being for the majority of the adult population, according to the research available to date. These ranges work for both genders and various adult age groupings; fit a variety of personal food preferences, eating styles, cultural needs, and financial budgets; and work for various disease conditions and exercise routines (from the evening walker to the professional athlete or body builder). These basic guidelines help to ensure adults are meeting their needs without exposing the body to dangerous excesses in nutrients.

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ATEAMSIS08 4/22/2021
It seems like everyday I go over on my protein and fiber goals. Report
CECELW 4/17/2021
i'm sure moderation is key Report
New ways, new news, old news, you never know Report
EEJAA70 1/8/2021
This is helpful information. Report
ELRIDDICK 10/11/2020
Thanks for sharing Report
MNABOY 7/25/2020
Do older people need more protein? Report
Thanks for the info Report
I've learned that nutritional intake is finely balanced to stay at the peak of being healthy. Report
Very interesting and informative article. Report
Good info. Thanks. Report
Still trying to find the right mix. Report
Everything in moderation, SparkFriends. Education is the key. Report
Very interesting. Didn’t know increased mortality rate varied because of plant versus animal protein. Report
While the macros mentioned are (maybe) correct for a healthy insulin sensitive adult at the correct weight, they are probably not great for an overweight diabetic. That "one size fits all" approach is exactly correct for all of the "one size" folks out there. Hmmmm... Let me start by sayin That Ain't Me!

So in the meantime, if I am trying to lose weight (and I don't fit the "one size, whatever THAT is) I will need a different macro set. I am told I'll be banned if I contradict Becky so... in the interest of remaining on the board... Do EXACTLY whatever Becky says.

For me, I care about losing weight. To do so my insulin has to go down because fat can't come back out of the fat cells if insulin is high. That much carbs is guaranteed to keep my insulin high and thus guaranteed to keep me fat. So the first thing I have to do is severely restrict my carbs.

For most insulin resistant folks that means less than 50 carbs. I try (and mostly succeed) to hold it under 20 carbs.

The next thing to know is that excess protein is broken down into glucose. Glucose causes my insulin to rise, again preventing me from losing weight. So while excess proteins will not hurt me, it will stop my weight loss. So for me, keeping my protein under about 4-5 ounces a day keeps my blood glucose low allowing me to lose weight.

How does this work for me?

I have lost 65 pounds, down from 305 to 240 this morning. My fasting blood glucose is normal, anywhere from 85 to 115 depending on the morning and what I have eaten recently. My A1C is 6.1 and dropping. My insulin resistance is slowly moving back to the normal range. I am off metformin, I control my diabetes solely with diet and intermittent fasting.

"One size fits all" isn't ideal and flat out doesn't work for me. But having said that do whatever Becky says because, as I was informed, she is the expert. Report
thank you Report
Thanks for the interesting article! :) Report
I am very happy with spark's suggested protien range. Before using the tracker, I did not realize that my diet was so low in protien & high in carbs. Now I try to reach the minimum suggested value of 60 gr/day. Report
Coach Becky, thanks for presenting multiple sides of a controversial subject...well done! Report
I understand that animal and vegetable protein is broken down by the kidneys. Any protein above what our bodies need is excreted in our urine. Do some research into the medical information and find out how much kidney disease we have in our country and you might guess that we don’t have a protein shortage problem, but a crisis of too much protein and an obsession to eat an abundance of it. The difference between animal and vegetable proteins is that it is metabolized differently, with excess vegetable protein having little to no effect on the kidneys. When we are young the kidneys can process the excess, but as we get older the kidneys wear out and stage 1-5 kidney disease sets in. At “end stage” kidney disease doctors will recommend a very low animal protein diet. My question would be, why wait till you have kidney disease at all to begin cherishing and honoring the organs that filter out the poisons in our bodies. Changing to a plant based diet asap will keep our kidneys functioning for our entire lives. After looking into the information or maybe having a close friend or relative with kidney disease, what do you think? Report
I realize I'm atypical as well. I can't do the whole carb thing, either. People used to laugh about how I was the only person they knew who gained weight when they went on a diet. Listen to your body; talk to your doctor. Low carb, moderate protein and higher fat works for me. I'd call it a modified Keto.

I learned this was the best for me through trial and error and I've come to know that if I eat too much protein, my blood sugar goes up to near pre-diabetic numbers. Not interested in becoming Diabetic.

I know it isn't the same for everyone but my doctor likes what he's seen and I love this way of life. Report
Great info. Thanks Report
Americans are obsessed with protein. Too little may be bad, but doesn't usually happen if you're taking in enough calories and eating healthy foods. Too much protein is at least as dangerous. It can leach calcium from your bones and contribute to kidney disease. Nice article on a timely subject! Report
I initially started with these macronutrient targets and quickly learned that my body did not tolerate carbs well. Sought out the support of a board certified clinical nutritionist and learned that I was not only gluten intolerant, I am grain intolerant. All grains have been removed from my diet and I am much healthier. My macro targets: carbs 30%, fat 40%, protein 30%. I realize that I am not typical. Report
60% carbs? Are you out of your minds?
A straight split 33/33/34 carbs/fat/protein works best for me, I've found, 12K cals or less. Report
My calories and carbs are always in range, but my protein intake is always way over and my fat intake way under. Most of my protein is meatless (unintentionally). I'm concerned I'm getting too much protein and how it may affect my health. Report
Everyone go vegan. It is so much fun and it doesn't lead you to binge since you are having so many carbs, fruits and yumminess. Report
Thanks so much for this great information!! I've been stuffing myself with yogurt of late and suffering with almost all of those symptoms! Will kick it back and wait for some improvement.
Rabbit meat diet can kill you not because of the low fat part, but because rabbit meat is missing an essential amino acid (or so I was told by a worldly friend). Rabbits evolved this way so that predators couldn't survive solely on them. For example, a snake who eats a rabbit must choose a different animal for its next meal or face an amino acid shortage. This leads to less dead rabbits. Too lazy to investigate further, but it's a reasonable explanation aside from too much protein. I think there are some recent papers... Report
Reading the comments and the article is interesting. "My sources say your sources don't have a clue" sort of thing.

This is why folks wind up saying "chuck the studies" and the advice and just do what they want to.

All bodies are generally the same. Dr.David Katz writes about this often. He is a public health physician. The studies show one can lose weight and keep it off on a variety of diets. Do what works for you. It's like exercise. Find what you will do and do it.

Simple. Not easy. Report
my bariatric physician says: no more than 30 grams per meal, your body doesn't really absorb more than that at a time, plus its just extra calories Report
The only problem I can see with too much protein, is your iron levels are going to sky rocket with a blood test. This can cause thickness in the blood and clotting if untreated can be quite dangerous. I personally do not have a lot of protein but my iron levels are high and I have to have blood taken every 2-3 months to reduce iron levels. Report
I'm not a protein girl. I thought 20% was recommended for protein, but if I only need 10% that's great. I can do that. Report
No wonder people are bailing from spark when you cannot bypass the advertising and survey unless you allow Voice Five to put a cookie on your computer. Nonsense. I'm going to My Fitness Pal. Report
...and what people routinely overlook in recommending "65% carbs and 1600 total cals" to people who are demonstrably prone to overconsumption is that high-carb eating stimulates appetite, making caloric restriction a continual test of willpower. Eventually hunger and frustration win out.

How much easier to focus on protein and fat, which despite being calorically dense actually satiate at lower intake levels. Imagine if your hunger actually worked for you rather than being your constant nemesis... Report
it is not carbs that make people fat it is excess carbs 50% to 65% of your calories from carbs will not make anyone fat if they only eat 1600 total calories. Report
45-65% carbs you've got to be joking thats the bad advise that is making people fat and unhealthy, increase good fats and protein (yes animal too) grass fed beef, organic poultry, wild caught fish etc full fat organic dairy, cut down grains they cause inflamation. Report
I will add that there is a difference between very low carb diets (such at Atkins) and the low carb diets (such as is my understanding of the Paleo and Ancestral diets). While the latter limit (or forbid) grains, they do include plenty of non-starchy vegetables, which I think few of us would argue is not a healthy choice. I personally am trying to get up to 10 or 12 servings of vegetables and 2 to 5 servings of fruit a day, but limiting my grain intake.

And to paraphrase at least one commenter below, to each his or her own. I couldn't survive a vegetarian diet, but I know many people who do very well on them and who probably wouldn't do well with the amount of meat I eat. Report
Hear, hear, Easternwawoman! Thanks for the links.

And what really makes me angry about the studies proving the evils of red meat is that there is no distinction made in many of these studies between healthy meats and processed meats. Of course if you study middle-aged people who consume a high-protein diet frequently consisting of hot dogs, salami, and balogna, you will find that they had "a 75% increase in mortality, a four-fold increase in cancer and a five-fold increase in diabetes."

In addition, there's a huge difference in the nutrient profile of conventionally raised and pastured meats.

I'm aiming for 40 to 45% carbs, 30 to 35% protein (which would be very difficult to attain from plants alone), and 25 to 30% fat in my diet, but this is quite new to me, so I can't say if it's working.

See Jonathon Bailor's work (The Smart Science of Slim) for a thorough investigation of the science.

And just call me a meat lover. If I go without red meat for too long, I binge. Report
I too concur with those who say that you can't believe everything you read about various diet programs. As someone said, every diet will inevitable serve some people. Personally, I've discovered my own successful diet ranges in regards to carbs, fats and proteins.

I like a high protein diet (I'm an active runner), however, most of my protein intake is not meat based. I love greek yogurt, cottage cheese as well as high protein nuts, grains and breads. Most days, my protein intake is at the higher end of the recommended range while my carbs are at the lower end the range with my fats being pretty mid range most of the time.

I'm in maintenance mode now and my program is working just fine. I've been maintaining the same 5lb weight range (140-145) since Jan 2013. Report
I remember reading in books on survival decades ago that rabbit was not viable for survival because of its low or no fat content. Combined with healthy fat it could be very good of course.

I tried Adkins and after several days felt run down and spaced out. Seems like my body likes carbs. Over many years I've learned that for me to lose weight I need to just cut way back on food of all kinds. Like a typical lunch might be half a chicken leg, and then a little something with carbs and fiber, usually vegetable, or maybe fruit. When I do that I feel good, am alert, do the same amount of exercise I do when I'm not dieting, and I lose weight quickly. Report
I gain over night if I consume that % of carbs. Just reverse the carbs and protein and you'll find that's what I try to eat. High protein, low carbs, mostly fruits, veggies, .
When I started Spark, used the menus provided. Way too many carbs.Had to make up my own meals, with my dietitians help. I cut the recommended % of carbs in half or less. It works for me, lost 185 lbs. Keeping it off. Report
This article is very helpful. As it says (and many of the people leaving comments say) the research is confusing. I have read many diet and nutrition books and they all make perfect sense at the time and have a lot of research backing them up. So how does one decide to go LC or HP or LF? Since there seems to be no consensus it seems best to eat a balanced diet, making sure most of the food choices are high quality, a mix of plant and animal proteins, healthy carbs consisting primarily of veggies, fruits and/or whole grains (both wheat and other grains), and some healthy fats (as everyone agrees Omega-3's should be stressed). The recommended percentages in this article allow one to select a high or low range of each food group that would meet individual needs without overdoing or underdoing on any of them. With the science conflicting and continually changing, this approach makes a lot of sense, and I thank Sparkpeople for some insights on this complicated issue. They are one of the few talking about balance. Report
Good reads from refereed research journal articles on this topic:

--Conclusion:A higher protein content of an ad libitum diet improves weight loss maintenance in overweight and obese adults over 12 months. There were no clinically relevant differences in changes in cardiometabolic risk factors among diet group.

An increasingly prevalent pattern of risk factors has emerged in middle-aged and older adults that includes the presence of type 2 diabetes or prediabetes, overweight or obese weight status with central obesity and very high body fat, low cardiorespiratory fitness (CRF), low strength, and a low lean-body-mass-to-body-fat ratio. Traditionally, these problems have been approached with a low-fat and low-calorie diet and with lower to moderate intensity activity such as walking. While the treatment has some clear benefits, this approach may no longer be optimal... Evidence is presented for shifting the treatment paradigm for disease prevention and healthy aging to include the DASH nutrition pattern but with additional protein, higher intensity, brief aerobic training, effort-based, brief resistance training, and structured physical activity

(Genetics at play..) Our data suggest that individuals with the FTO rs9939609 A allele might obtain more benefits in a reduction of food cravings and appetite by choosing a hypocaloric and higher-protein weight-loss diet.


Previous work has shown that hunger and food intake are lower in individuals on high-protein (HP) diets when combined with low carbohydrate (LC) intakes rather than with moderate carbohydrate (MC) intakes and where a more ketogenic state occurs.

High protein intake is associated with low prevalence of frailty among old Japanese women: a multicenter cross-sectional study.

This is the first study that demonstrated that a high protein, hypocaloric diet were associated with improvement of lipid profile, glucose homeostasis and liver enzymes in NAFLD independent on BMI decrease or body fat mass reduction.
Having just learned that I am "pre-diabetic", what would the macronutrient ranges be for a diabetic? Thanks. Report
I like the comments that call "bs" on this article. People who take things as fact simply because they are written are asking for trouble. And I agree, that you cannot trust a lot of these studies, as the Ones conducting them often have an agenda. I like a high protein, low carb diet, and so does my body. The minute I eat ANY sort of pasta, rice, or bread, I see the difference on the scale the next morning. Let's face it, these foods convert into sugar, and sugar is the enemy! (for me at least). I will never be convinced that adding carbs (other than fruits and veggies) is conducive to good health, and especially weight loss. Report
I wonder if all these folks that are eating "low carb" are not eating fruits and vegetables. They are almost entirely carbohydrate.

I agree that what works for one person may not work for others. The people who historically eat a lot of meat, such as the Inuits mentioned, have adapted to that diet over thousands of years. Report
I am actually familiar with that study mentioned. It's an utter and complete joke.
1st off, the author is the owner of a vegetarian base company that sells detoxes
That right there should be enough to realize that this has been set up to be biased.
Next, it was done only questionnaire and with a small sample group compared to studies with a much larger based that found the opposite
It did not account for pre-existing conditions. People who had diabetes and reported eating a high protein diet, got listed as protein causing their death. wtf?
It even contradicts itself, saying that mortality rate goes down if you eat high protein after age 65. Come on.
Their "average" diet was 16% protein.
Take nothing on account of activity level or starting weight into consideration

The amount of actual science done in this study would have received a reprimand on a 4th graders science fair project. Report