How much protein can you eat in ketosis?

How Much Protein Do I Need on Keto? Find Out What Science Has to Say

It’s no surprise that many gym-goers, athletes, and active individuals alike presume that they should eat tons of protein. After all, protein is generally thought to be a “good thing.”

So, the more, the better, right? Well, not really.

Consuming excessive amounts of any essential nutrient, whether it’s protein, fat, vitamins, or minerals, isn’t conducive to optimal health and performance. The same can be said for not consuming enough of those nutrients.

If you’re a low-carb diet advocate, you might be curious how much protein to eat on keto.

The short answer: Not nearly as much as your intuition might tell you, even if you’re trying to build muscle. 

Read on to learn all about how much protein you should eat on keto.

Protein Intake on Keto: Examining the Evidence

Health and nutrition aren’t as black and white as countless “gurus” and “experts” would have you believe. There are many shades of grey to consider when it comes to things like food choices, nutrient needs, and dietary supplements.

Conventional “gym bro” wisdom tells us that high-protein diets are optimal when you want to get lean and pack on muscle. Consequently, bodybuilders and athletes might end up consuming 2+ grams of protein per pound of body weight per day.

Heeding this advice, let’s say Joe Bodybuilder - who weighs 180 lbs - eats 360 g protein/day. Is he going to build more muscle than if he were to eat only 180 g protein/day?

The extant research suggests the answer is a resounding “no!”

There are virtually no studies to suggest that eating more than 1 g protein/lb body weight/day has beneficial effects on muscle function and athletic performance [1].  The notion that copious amounts of protein are necessary for optimizing muscle protein synthesis and mitigating muscle protein breakdown is baseless.

In fact, research contends that healthy adults only require about 1.2 g protein/kg body weight/day [2]. Since one kilogram is equal to roughly 2.2 pounds, that means the average adult should aim for about 0.55 g protein/lb body weight/day. Larger and more active people stand to benefit from eating a bit more, as do the elderly [3].

For active adults who train with weights 4-6 times per week and want to pack on muscle mass, a slightly higher amount of protein is recommended, anywhere between 0.8 - 1.15 g protein/lb body weight/day.

How Much Protein to Eat on Keto

Those who follow the keto diet may benefit by eating just a tad more protein than those on higher-carb diets since carbohydrates are protein-sparing [4]. Therefore, people who consume plenty of carbs actually need less protein and vice versa.

If you’re new to keto, aim for 1.1-1.3 g protein/lb body weight/day.

For example, if you weigh 170 lbs, you should shoot for a daily intake of roughly 185 to 220 g protein on keto. Since protein has 4 calories per gram, that’s between 740 and 880 calories from protein per day. The majority of your remaining calories should come from fats, which have 9 calories per gram.

Carbs will contribute a small amount of energy to your diet as well. However, the goal on keto is to keep your carb intake as low as possible, ideally 30 g or less per day.

Is a High-Protein Keto Diet Best?

Anything beyond the previous recommendation for protein intake on keto isn’t necessary, nor will it provide greater benefits for muscle growth or muscle preservation.

Also, keep in mind that eating too much protein on keto can actually be counterproductive by increasing gluconeogenesis and consequently reducing ketone production.

What is gluconeogenesis, you ask?

In layman’s terms, gluconeogenesis is when the body uses amino acids to create glucose. It’s simply another one of the many physiological pathways that the body uses to provide energy to cells.

For example, when you fast for an extended period of time, the liver will start to produce more glucose from suitable non-carbohydrate molecules, such as lactate, glycerol, and certain amino acids.

Hence, gluconeogenesis is a necessary pathway for survival during periods of starvation and extensive fasting.

While small amounts of gluconeogenesis will occur on any low-carb diet, it usually has a negligible impact on ketone body production and ketosis. Be wary, though, that eating excessive amounts of protein can upregulate gluconeogenesis by essentially “flooding” the body with a surplus of amino acids.

Not all of the protein (amino acids) you consume go towards creating new muscle tissue. If that were the case, we’d all be as swole as swole gets. If you eat 100 grams of protein in a meal, only so much of those amino acids will be used for synthesizing muscle protein.

Several studies have shown that about 30 grams of a leucine-rich protein source (e.g most animal and milk proteins) is enough to maximize the muscle protein synthesis (MPS) response to a meal [5, 6]. The rate of MPS remains above baseline for 3-5 hours thereafter, depending on the protein source(s).

Now, does this mean you must restrict protein consumption to 30 grams per meal for optimum muscle growth while limiting gluconeogenesis on keto?

Certainly not.

It simply tells you that you don’t need to eat tons of protein on keto (or any other diet) in order to optimize muscle growth and muscle retention.

Although, eating plenty of protein on keto can provide other benefits.

For one, protein is a satiating nutrient and has a higher net thermic effect of food (TEF) than fat and carbs [7]. In other words, your body requires more energy to digest and absorb foods like meat, eggs, and poultry as opposed to grains and butter.

Furthermore, the amino acids that don't go towards protein synthesis are still biologically useful for other roles in your body aside from gluconeogenesis (e.g. creating neurotransmitters, supporting immune function, regulating blood pressure, etc.).

Protein is also more “tricky” for the body to convert fat when it’s consumed in excess, but it is possible. As such, you don’t want to get too carried away with your protein intake on keto.

Anything beyond 1.5 g protein/lb body weight/day is teetering on superfluity.

Best Keto Protein Sources

The best keto protein sources are foods that generally fulfill three requirements:

1. Low/no carb content
2. A complete profile of amino acids (and a high proportion of L-leucine)
3. High digestibility and bioavailability

There are quite a few keto protein sources that meet these needs, whether you’re someone who eats animal products or on a plant-based diet. The main thing to remember is that the rate of muscle protein synthesis after eating is proportional to the essential amino acid profile of protein(s) ingested [8].

Hence, it doesn’t matter if you consume a single complete protein source or if you “mix and match” several incomplete protein sources in a meal to get all the essential amino acids necessary for optimizing protein synthesis.

Meat, poultry, seafood, eggs, soy, and dairy are sources of complete protein. Most plant foods, such as lentils, legumes, vegetables, grains, nuts, and seeds, are incomplete protein sources.

As such, some of the best keto protein sources for meat-eaters include:

The great thing about the keto diet is you no longer have to be scrupulous about which meats and seafood you eat or how lean they are (since you need fat, especially when carb intake is low). This means fatty steak cuts and even 80/20 or 75/25 ground beef are suitable for keto.

If you follow a plant-based keto diet, you might need to use a plant protein powder, like pea protein or rice protein, to help meet your protein needs. This will help keep your carb intake low enough for ketosis while boosting your protein intake.

Keto Protein Sources to Avoid

There are a few foods to avoid / moderate when you’re selecting protein sources on keto, including:

• Processed deli meats (e.g. smoked turkey and cured honey ham) that are high in sugar. When in doubt, opt for fresh meat, poultry, and seafood and always check the food label to be sure there aren’t tons of added sugars that can take you out of ketosis.

• Breaded meats (e.g. chicken nuggets and fish sticks) that are coated in a high-carb batter. You will usually find breaded meats and seafood in the frozen food aisle at the supermarket, so be careful to avoid these as they can pack quite a bit of “hidden” carbs into your keto diet.

• Glazed meats and poultry (e.g. teriyaki chicken and BBQ ribs) that contain sugary coatings. Conventional glazes and sauces are almost always loaded with sugar, cornstarch, and other carb-laden additives.

Is Keto Bad for the Kidneys?

There is a long-held notion among the general population that the kidneys are the major site of protein metabolism and a high-protein diet is bad for the kidneys. This presumption is flawed for several reasons...

Firstly, protein is predominantly metabolized in the gut since the enzymes that hydrolyze polypeptides into individual amino acids and oligopeptides are primarily located in the stomach.

Once protein is sufficiently broken down, the short amino acid chains and isolated amino acids may go on to play a myriad of biological roles, such as helping synthesize new muscle tissue, producing neurotransmitters, and providing energy for cells.

The kidneys aren’t necessarily involved in protein digestion; rather, they help remove the metabolic (nitrogen-rich) waste that develops as a byproduct of protein metabolism. In humans, the major byproduct of protein metabolism is ammonia, which is subsequently converted to urea in the liver and then transported through the blood to the kidneys so it can be filtrated and excreted via urine.

Technically, the urea cycle in the liver is the final point of protein metabolism.

Thus, the kidneys are like the “trash collectors” of the body since they pick up this metabolic waste from protein metabolism and help flush it out of the system.

So, yes, the kidneys do have to work “harder” when you consume more protein, but it’s not in the sense that most people believe. Healthy kidneys can tolerate a high-protein keto diet in a fairly seamless fashion and there isn’t much compelling evidence that high-protein diets cause renal impairment.

But before you go and slam another scoop of protein powder, there are some finer points to consider when it comes to a high-protein keto diet and kidney health.

High-Protein Keto Diet and Kidney Health: Should You Be Concerned?

The majority of people who switch to the keto diet are likely to be eating more protein than they did on their previous diet. Naturally, this may cause some concern about whether the higher protein intake will damage their kidneys.

The short answer: No, it won’t, so long as you don’t have preexisting renal impairment or kidney disease.

However, not all protein that we ingest is made equal. Animal proteins tend to be the most “stressful” on the kidneys because they are more acidic and result in a greater increase of glomerular filtration rate (GFR).

The GFR is a numerical measure that depicts the rate at which filtered fluids flow through the kidneys. This filtered fluid passes through the kidneys and subsequently becomes urine that is  passed to the bladder.

Plant Proteins Support an Alkaline Diet

The modern Western/American diet is without a doubt more acidic than it has ever been before. While the acidity of the diet doesn’t necessarily determine its healthfulness, excessive acidity has been shown to impair kidney function over time [9].

Most animal meats and fish are highly acidic due to their greater proportion of sulfur-containing amino acids, particularly methionine and cysteine. To compensate for the acidity of these protein sources, the body needs to buffer the blood to restore a more alkaline state.

One way the body does this is by leaching calcium out of the bone matrix and into the bloodstream. However, this can be problematic since nearly all (99%+) of the calcium in the body is stored in bones [10].

In turn, if you consume mostly acidic proteins, your bone mineral density may suffer and you’ll be at a greater risk of fractures and conditions such as osteoporosis.

What’s interesting though is that protein-rich carnivorous diets actually seem to be more effective for reducing the risk of bone fractures and osteoporosis, while plant-based diets have been shown to reduce bone mineral density [11, 12].

Nevertheless, diets that contain large amounts of animal meat and fish are associated with a greater risk of developing kidney stones (especially if dietary potassium is lacking) [13].

This may all sound like doom and gloom for people who like to eat things like bacon and steak on keto, but the good news is that the acidity of these protein sources can be attenuated by potassium-rich alkaline foods, particularly low-carb vegetables and fibrous fruits.

For those on keto, you can certainly go ahead and enjoy your t-bone steak dinner, but be sure to include a side of veggies to help keep the acidity down and protect your kidneys.

Summarizing Protein Intake on Keto: Things to Remember

As mentioned earlier, health and nutrition aren’t black and white. Many factors play into how much protein you should eat on keto, such as body weight, sex, age, genetics, and lifestyle. At the end of the day, you will need to do some experimenting to find the optimal protein intake on keto for your body!