How Too Much Protein is Bad for Ketosis

One of the well-known mantras of the ketogenic diet is very low carb intake and high fat intake. But there’s another nutrient that’s important to monitor when going keto—and a lot of people make the mistake of not considering its importance. That would be protein.

Although protein is a critical element in the diet we need for optimal health, it’s important to not eat TOO much protein on the ketogenic diet. Why? Well, there are a couple reasons that we’ll be discussing below.

How Too Much Protein is Bad for Ketosis

The biggest energy source on the ketogenic diet is fat. In fact, around 75% of your diet should come from healthy fat sources. The key here is that, unlike the traditional idea of low-carb diets where protein is higher, protein intake should bemoderate, not high, on keto. Not following this advice will never allow your body to enter ketosis, which is the main point of going keto and reaping all of the amazing benefits.

The reason too much protein is bad for ketosis is because our bodies have a fundamental energy process called gluconeogenesis. For a deeper dive into the topic, see our post on fixing the biggest ketosis mistakes. For now we shoud know the basics. Let’s break it down this mouthful of a term. The word gluconeogenesis has three parts to it,
Gluco – coming from the greek root glukos – literally meaning “sweet wine.”
Neo – “new”
Genesis – “creation”
So a great way to think about it is this is how your body creates new sweet wine for your body. Some people tout that “you don’t need carbohydrates to survive,” which is only partially true. To clarify, you don’t need to eat any carbs to survive, but make no mistake, your body needs carbs in the form of glucose and glycogen, and it will get this via survival mechanisms like gluconeogenesis.

Why Gluconeogenesis is Bad for Ketosis

The body’s preferred source of fuel is glucose, which it gets first from carbohydrates on a standard diet. However, if enough carbs aren’t present, which is the case when you’re eating low-carb or ketogenic, the body will have to turn to other sources for energy.

The purpose of the keto diet is to have the body break down fatty acids, which then produces ketones for energy—the process known as ketosis. Those following a ketogenic diet know that monitoring ketones in the body is how you know you’re in ketosis.

However, there’s another way the body can create carbohydrate-style energy in the body—by breaking down amino acids from the protein in your muscles. Gluconeogenesis (GNG) is how your body turns protein into glycogen that can be used as glucose to burn for fuel.

Why is this bad? There are two big reasons:

  • When the body turns to protein for fuel, it keeps your body from going into ketosis. This stalls any long-term progress from the keto diet and you won’t reap the benefits that come from using ketone bodies for energy, burning through fat, and reducing your body’s reliance on carbs for fuel.
  • Plus, it’s bad news when the body turns to your lean muscle mass for fuel. This isn’t good for your physique, or your physical performance, or your health.

Avoiding Too Much Protein

Even if you’re eating plenty of fat, if you also eat too much protein, your body can facilitate GNG instead of burn fat for energy. This means that you could spend your whole time thinking you’re eating keto while not actually being in ketosis. And who wants to go to all that effort without getting actual results?

The key is to maintain a high amount of fat intake, a moderate amount of protein intake, and a very low carb intake. This ensure your body still has the adequate protein it needs for cell and tissue function and muscle growth.

What to Measure: Protein and Ketones

There are two main ways to make sure you enter and stay in ketosis in regards to protein: (1) figuring out the amount of protein that’s right for you without it being too much (or too little) and (2) measuring your ketone levels.

Measuring Protein

For those who aren’t endurance athletes and expend a normal amount of energy each day, the macronutrient percentages on the keto diet are generally:

  • 75% fat
  • 20% protein
  • 5% carbohydrates

Also, a good protein rule of thumb per day is typically around 0.7 to 0.9 grams of protein per pound of lean body mass. Go on the high end for workout days and low end for rest days.

Still, these percentages and numbers are quite vague and hard to calculate without knowing your specific measurements. What’s tricky is that it all depends on your individual needs.

You can follow this process for determining your protein requirements on the ketogenic diet:

  • Calculate your calories on the site, then enter the nutrient percentages above (60% fat, 35% protein, 5% carbohydrate) to calculate your gram totals per nutrient group. Use this as your starting point for the amount of daily protein you consume. (You can see this post for my experience modifying my meals to moderate amounts of protein for ketosis.)
  • From there, you can monitor your ketone levels to ensure this amount is right for keeping you in ketosis. Then, it’s important to strictly stick to that number each day. Even the smallest variation can mess with your results!

You should also note that your protein numbers might change as you stick to keto and experience any weight and fat loss, so continue to re-calculate your weight and calorie intake regularly—around every other week.

Measuring Ketones

Even if you think you have your macros on point, the only way to truly know if you’re in ketosis is by measuring it. There are three main ways to test your ketone levels: through urine testing, blood testing, or breath testing. (Our testing guide covers the different ways to test your ketone levels.)

how to test ketone levels

Including exogenous ketones is another great way to help get yourself back into ketosis immediately. It’s a good idea to have some of it available during the process. If you eat too much protein, they can bump you right back into a ketogenic state. Need some ideas on moderate protein meals? Dr. Gustin has us covered for keto breakfasts.

Test frequently, paying close attention to your macros and how your readings respond after you eat. If you keep the idea of moderate protein in the back of your head, it can help you remember to not overdo it at each meal. With this information in mind and a lot of discipline, you’ll be rocking full-blown ketosis and reaping the rewards before you know it.

Remember that low-carb does not guarantee ketosis. You could eat zero carbs and not be in ketosis. Too much protein will take the keto out of your ketogenic diet. Test don’t guess 🙂

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Responses (43)

  1. Is there an author for this page? I would like to use this information in a paper I’m writing and having an author would make it easier to cite properly.

      1. I haven’t been eating Keto very long but I have the strips and I’m stay in Ketosis most of the time. Have a question. I’m getting to where I’m not very hungry in the afternoon which is new for me!! BUT do I need to eat something to keep me in Ketosis or wait till dinner time kind of thing. Also if I eat less Bc I’m not as hungry at dinner will that throw me off also?… thanks

        1. Great to hear! If you are in ketosis your body will have the metabolic flexibility to use the food you eat and/or your own body fat. So you don’t have to eat if you aren’t hungry, your body has about 40K calories of fat in storage ready for action! 🙂

  2. Is the glucose meter the same as what diabetics use to test? If so what values are you looking for? If not do you have a meter you recommend? We think we have been in ketosis for over a week (next to the darkest color on the strip and eating about 16 carbs a day on average with about 75-80%fat) and we aren’t seeing anything other than a little water weight .. no BMI change. Any suggestions?

  3. I have a problem measuring protein from meat : say I cook with 250g frozen meat. Result : say 160g cooked meat, with the juice and fat in the pan. How much do I record : the frozen meat ? the cooked meat ? with or without the juice and/or the fat ? I can’t find the answer anywhere and it makes a world of difference. Can you help ? Thanks !

      1. The problem with the MyFitnessPal app is that you must pay a monthly fee in order to receive the full benefit of the app. Some of us can’t afford regardless if it’s a small amount or not.

        1. Use the “MyPlate” app. You set your micros for free! You can either barcode scanner your food or manually enter it in. Super easy!!

      2. I have tried the MyFitnessPal app but looking up the food is just a guessing game. There are so many people putting their own food entries in that you don’t know which is accurate and which ones are just being guessed at. I think they should never have allowed everyone to put entries in. It was so confusing that I had to stop using it. Any other options?

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  6. 75, 20, 5 is an ideal ratio but is there a higher protein, lower fat percentage you can have and still be in ketosis? Some days I find it hard to eat that much fat.

    1. Absolutely! It’s called modified keto…check it out. Moderate protein, medium day. Eating 20g carbs or under daily will guarantee ketosis within several days.

  7. “However, there’s another way the body can create carbohydrate-style energy in the body—by breaking down amino acids from the protein in your muscles. Gluconeogenesis (GNG) is how your body turns protein into glycogen that can be used as glucose to burn for fuel.”

    I agree that it would prevent the body from entering ketosis, but I don’t understand why the body has to eat the protein from muscle and not from the proteic foods you eat.

  8. I think there is some misconceptions in this article. Gluconeogenesis is NOT bad for keto, it is actually the mechanism by which non-carbohydrate sources turn into energy (be it protein or fat). You need gluconeogenesis to create ketones, after all.

    1. If you’re arguing that you always need a little bit of glucose and insulin, that is correct. However most of the response people will have is that it drives up insulin too much. Ketones are produced via beta oxidation from fat.

  9. In this article you stated
    “Calculate your calories on the site, then enter the nutrient percentages above (60% fat, 35% protein, 5% fat) to calculate your gram totals per nutrient group. Use this as your starting point for the amount of daily..”

    Did you mean 5% carbs?

  10. If im fasting and in ketosis, will eating the same amount of protein as usual throw me out of ketosis? Will the body just utilize the protein for muscle repair or will it turn it into glucose?

    1. Hey Luke, it really just depends on how your body reacts to different amounts of protein – it’s very individualized. I would recommend testing your blood ketones to really find out!

  11. Hi

    As per the lean mass calculation my protein macros are around 65. But if I calculate as per percentage then 35% protein and cal intake being around 1200 my protein is higher. Around 105. So which macro do I follow ?

    I did 1 round of keto in April for 2 months with protein between 60-70 and fat around 80 and carbs below 20. Lost 7 kg. Was doing some cardio then
    Have started lifting weights thrice a week now and increased protein to 100 with rest being same … I am not loosing at all. So I am really confused which macros to follow. If I go back to my round 1 macros then will I be able to lift heavy ?

    1. Hi Pooja, the macros from round 1 sound like they were spot on and it seems like you had great success with those numbers. I would try that out again for a few weeks and see what happens. You’re body may need a few days to adjust back again and it could hinder your lifts in the beginning but then you should be right back to lifting heavy in no time. Ketones are muscle sparing and you don’t need as much protein as you may think to lift heavy and gain muscle!

  12. So, my morning consists of a scoop of vanilla exogenous ketones in some coconut milk, then I will have a coffee with heavy whipping cream and the perfect keto mct powder. I hold off on lunch until noon. I use urine testing strips to see if I’m in ketosis and it comes up as barely being in it on the lighter side of the spectrum. I eat protein and fat with little carbs, only coming from veggies. Is there a reason I’m not seeing a darker color on my strip? I’m starting to think it isn’t working at all to get me into ketosis. Any insight would be appreciated!

    1. Hey Katie, the urine strips are useful to see if you are producing ketones but I would not get too caught up on the color (how dark or light it is). If you’re feeling great and seeing results – keep doing what you’re doing! Also, once you are keto for a while, the urine strips may not be as accurate because they measure the amount of ketones you are “dumping” – so if you become more efficient at using those ketones for fuel (which you will the longer you’re keto) than you won’t excrete as much in your urine…make sense?

  13. Thank you for the information, AND the questions! I am new! Have been on keto since December 4. I have 70/25/5. It has been challenging for me to get the macros in the right place. I have had trouble with the fat portion and read about fat balls. Any comments on those? It is amazing to me to think that 17 days ago I was over 300 lbs. Now I am at 285. Today, I was way over in the carbs, 43g! Oh man, I feel so bad about it! This is how I came across your page. Protein has been higher than recommended. So, thank you for your page, and the questions. I don’t miss sugar, or that 20 lbs! But I do want things to keep moving.

  14. Is gluconeogenesis demand-driven or supply-driven? The idea of too much protein causing increased gluconeogenesis only makes sense if it is supply driven. But the consensus seems to be that gluconeogenesis is demand-driven–the body can turn protein into glucose >if< it needs to. Otherwise, body builders and powerlifters, who consume protein in quantities that would be absurd if the protein just turned into glucose, would be unable to turn that protein supply into muscle. Do you have references to the contrary?

  15. Hello! Just came across this blog. This is my second attempt at keto. I have the urine strips to test for now. What if I’m at roughly a 73, 25, and 3 ratio? Am I hurting myself greatly by the elevated protein and not enough of the others? I use the myketo app. I try to measure using the published nutrition values on the protein I eat.

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