It is said that protein can kick you out of ketosis and is hard on the kidneys. But is it really? Let’s find out how much protein you should really be eating on a keto or low-carb diet – it might be way more than you think.
Table Of Contents
- The importance of protein
- Isn’t keto higher fat than protein?
- Will too much protein kick me out of ketosis?
- What about gluconeogenesis?
- I’m not a bodybuilder, should I still have a high protein diet?
- Is protein bad for the kidneys?
- How much protein should we eat?
- What’s the ideal amount of protein on keto
The importance of protein
Did you know that you are MADE OF PROTEIN? That’s right. Protein and fat are the two essential macro-nutrients (nope, carbohydrate isn’t in the essential list) because our bodies do not function without them. Protein, specifically, is the building block: it’s what our bodies are made off – our cells, muscles, nails, hair, skin, and even our bones!
Some symptoms that are really common among people on keto and low-carb diets can be associated with a low protein intake: hair loss, brittle nails, skin rashes, and an increased appetite and persistent hunger (10).
So, why is protein vilified by many keto dieters? Why the widespread belief that protein will kick you out of ketosis? Why the stories of excess protein being bad for your kidneys?
Although plastered all over the internet, the idea that the protein intake must be lower than fat in a ketogenic diet is a myth. It stems from a strict medical version of the diet, created to treat patients with epilepsy. But for the weight-loss dieter, who is not trying to control seizures, limiting protein is not only unnecessary, it makes the keto diet much harder to follow.
Let’s go ahead and demystify protein, this beautiful molecule that is so misunderstood.
Isn’t keto higher fat than protein?
Contrary to common belief, it doesn’t matter how much fat you ingest in the keto diet. The only macro-nutrient that’s key to the keto diet is carbohydrate: keep the ingestion of carbs low enough, and your body will be forced to burn fat for energy instead of glucose (1). That’s what “being in ketosis” means.
The myth of keto being a high fat diet originated from the most popular and studied medical application of keto, as in a diet to prevent epileptic seizures in children. Which was, not at all, a diet intended for fat loss.
This strictly medical keto diet was high in fat for two reasons: to provide an increased amount of ketones reaching the brain to reduce (and in several cases completely stop) seizures, AND to prevent the children patients from losing too much weight and impeding their physical development.
Therefore, if the intent on a keto diet is to lose body fat, then the consumption of fat needs to be reduced. Dietary intake will take precedence for energy burning, which means that if you eat all the fat needed for your body to burn as energy then it will not dip into its stored fat reserves.
Will too much protein kick me out of ketosis?
No, this is also a myth. For a healthy individual following a keto or low carb diet the ingestion of protein can even help with ketone production, because protein is related to an increase in glucagon levels. Dr. Benjamin Bikman explains in detail in this lecture the relation between glucagon, ketones and protein intake. If carbohydrate intake is limited, you can have a high protein diet and still remain in continual ketosis (11, 12).
If a person has, in the other hand, insulin resistance, and follows a standard American diet, then protein is in fact bumping up insulin (11). Protein will spike insulin when it is ingested together with glucose. Insulin when present in high levels will impede the liver from creating ketones.
What about gluconeogenesis?
Gluconeogenesis, another word much maligned in the keto community, is rumored to occur when someone eats too much protein. Gluconeogenesis is a demand driven process in which your body produces glucose – but it will only occur when it’s necessary, not because protein (or anything else) has been ingested. It’s impossible to force the body to over produce glucose above the level it needs (1).
Also important to note, gluconeogenesis can occur using not only using protein as a substract (1), but also glycerol (fat). The very first option for gluconeogenesis, though, is lactate (a by-product of glucose used in muscle cells). So, in the end, GNC will happen if needed, whether you eat protein or not.
We should all be thankful to gluconeogenesis: it is what makes a ketogenic diet possible. It provides glucose to the cells in our bodies that need it, without us having to eat any carbs at all.
I’m not a bodybuilder, should I still have a high protein diet?
Not a bodybuilder? Wrong! As brilliantly explained by Dr. Ted Naiman in this video, everyone is a bodybuilder. You might not have realized it yet, but every choice you make, for everything you put into your mouth to how (and if – couch potatoes beware) you move has a directly relation to the composition of your body.
You can build yourself into a flabby mass of fat and lose skin and weak bones, or you can build your body into an amazing muscular, strong and powerful machine. You are the builder. Your body is just a reflection of how much thought and care you put into it. And the best thing about this actionable philosophy is: Everyone can do it. Everyone is doing it, without even knowing it. And it does not matter your age, so it’s never too late to start (7)!
Is protein bad for the kidneys?
The dietary restriction of protein is a common treatment recommended for people with renal disease, and there are guidelines limiting protein for kidney patients by the National Kidney Foundation (NFK). These recommendations are not indicated for individuals with normal renal function (3). Furthermore, the only kidney patients that respond positively to a protein restriction diet are males suffering of glomerular disease, which constitutes only a small percentage of those with a kidney condition (5). Still, the mere existence of these guidelines is enough to make the “protein is hard on kidneys” myth take off.
The lay public is often told that high protein diets cause “overwork” (hyperfiltration) in the kidney and may negatively impact renal function over time. That is not true. Athletes habitually consume “excess” protein and there is no evidence that they are at greater risk for losses in renal function (3). Also, people who live with only one kidney in prolonged hyperfiltration do not show abnormality in the long term. Hyperfiltration appears to be a beneficial biological adaptation (3).
How much protein should we eat?
The population has been led to believe, following the Recommended Dietary Allowance (RDA), that eating just 0.8 grams per kilogram (0.36 grams per pound) of body weight of protein per day is enough. Many preach that eating more than that is unnecessary or just plain harmful. That couldn’t be farther from the truth (11).
The nutritional requirements suggested by governmental entities do not take into consideration that an individual can eat to improve one’s health, by optimizing diet and physical activity. All they care about is that the population will not end in a hospital for malnutrition.
The RDA is actually the minimal amount that a human being needs to survive (8). As in, not die. Ask yourself, do you want to eat only enough protein not to die from the lack of it? Is that how we should approach nutrition?
The ideal amount of protein for optimal health is indeed much larger than the bare minimum: A new study (9) using a modern test to determine protein requirements proposes that 1.5 to 2.2 grams per kilogram (0.7 to 1 gram per pound) of a variety of high-quality proteins (of animal origin) per day constitutes a reasonable recommendation for the average adult.
What’s the ideal amount of protein on keto
This is a tricky question: we just exposed that the only macronutrient that’s important for maintaining ketosis is carbohydrate. But, depending on your health circumstances, when starting a keto diet there are two options for best results:
1. High protein option
If you are doing keto for a while and are fully fat adapted, or if you are just starting your keto diet but have a healthy metabolism, with no insulin resistance or a diabetic condition, you don’t need to limit your protein intake. The ideal amount of protein for keto or low-carb in this situation would be the around the same as the recommended for all humans: around 1 gram per pound of body weight, and there is no harm in eating more than that (9, 12).
In macro numbers, this can be a proportion of 1:1 grams of protein to fat, or slightly higher in protein. People can be on continual ketosis at 30% protein or more (2, 6). Remember, the amount of protein will not decrease your ketone levels as long as your carbohydrates – and blood glucose – are very low (11).
If you are interested in building lean mass, especially, you will benefit from a higher protein range. You’ll also benefit from more protein the longer you’ve been on this Earth, as our bodies are less efficient in making protein available for our muscles as we age (8, 12).
2. Lower protein option
If you are starting a keto diet with impaired insulin sensitivity, from either pre-diabetes or type 2 diabetes, then in the beginning it’s best to keep protein at a moderate level, as the ingestion of protein in presence of glucose will cause spikes in insulin, which in turn does not help promote a ketogenic state (11).
This would translate to a moderate protein amount around 20% to a maximum of 25%, with up to 5% carbohydrates, and the remaining calories from fat. Specially when protein is at the lower range, it’s important to make sure to think of protein as a “goal” macro: eat the whole amount you are supposed to.
One of the most important benefits of the keto diet is the reversal of insulin resistance, and even the possible reversal of full-blown diabetes, making your organism once again metabolically flexible.
After your body regains balance and you are fully adapted to burning fat for fuel, which can take from a few weeks on keto to a few months depending on your personal circumstances, you should then start introducing a higher amount of protein (11) and lowering the fat towards a “to satiety” amount, not a specific macro percentage to be reached.
2 Fromentin C, Tomé D, Nau F, et al. Dietary proteins contribute little to glucose production, even under optimal gluconeogenic conditions in healthy humans
3 Martin WF, Armstrong LE, Rodriguez NR Dietary protein intake and renal function
4 Jane E. Kerstetter, Kimberly O. O’Brien, Karl L. Insogna Low Protein Intake: The Impact on Calcium and Bone Homeostasis in Humans
5 Rosman JB, Langer K, Brandl M, Piers-Becht TP, van der Hem GK, ter Wee PM, Donker AJ Protein-restricted diets in chronic renal failure: a four year follow-up shows limited indications
6 Klement, Rainer & Frobel, Thomas & Albers, Torsten & Fikenzer, Sven & Prinzhausen, Jan & Kämmerer, Ulrike A pilot case study on the impact of a self-prescribed ketogenic diet on biochemical parameters and running performance in healthy and physically active individuals
7 Mayhew DL, Kim JS, Cross JM, Ferrando AA, Bamman MM Translational signaling responses preceding resistance training-mediated myofiber hypertrophy in young and old humans
8 Stuart M. Phillips, Stéphanie Chevalier, Heather J. Leidy Protein “requirements” beyond the RDA: implications for optimizing health
9 Paul B. Pencharz, Rajavel Elango, Robert R Recent developments in understanding protein needs – How much and what kind should we eat?
10 Pezeshki A, Zapata RC, Singh A, Yee NJ, Chelikani PK Low protein diets produce divergent effects on energy balance
11 Dr. Benjamin Bikman – Insulin vs. Glucagon: The relevance of dietary protein Lecture
12 Dr. Ted Naiman – Nutritional Ecology and Protein Leverage Lecture