Along with fat and carbohydrates, protein is one of the three macronutrients (“macros”) found in food, and it plays unique and important roles in the body.1 Here’s a guide to everything you need to know about protein on a low-carb or keto lifestyle.


 

What is protein?

Protein is made up of several smaller units called amino acids. Although your body is capable of making most of the 20 amino acids it needs, there are nine that it can’t make. These are known as the essential amino acids, and they must be consumed in food on a daily basis.2

Because animal foods contain all 9 essential amino acids in roughly the same amounts, they are considered “complete” protein. By contrast, plants lack one or more essential amino acids and are referred to as “incomplete” protein.3

Keto-friendly animal protein sources include meat, poultry, seafood, eggs and cheese.

Keto-friendly plant protein sources include most nuts and seeds, although some are higher in carbs than others.

What does protein do in your body?

Protein is a major component of every cell in your body. After you eat protein, it is broken down into individual amino acids, which are incorporated into your muscles and other tissues.

These are just a few of protein’s important functions:

  • Muscle repair and growth. The protein in your muscles is normally broken down and rebuilt on a daily basis, and a fresh supply of amino acids is needed for muscle protein synthesis, the creation of new muscle. Consuming adequate dietary protein helps prevent muscle loss, and – when coupled with resistance training – promotes muscle growth.4
  • Maintaining healthy skin, hair, nails, and bones as well as our internal organs. Although the protein turnover in these structures occurs more slowly than in muscle, new amino acids are required to replace those that become old and damaged over time.
  • Creation of hormones and enzymes. Many of the hormones necessary for life – including insulin and growth hormone – are also proteins. Likewise, most enzymes in the human body are proteins. Your body depends on a continuous supply of amino acids to make these vital compounds.

In addition, getting enough protein can help make weight control easier.

For instance, protein has been shown to reduce appetite and prevent overeating by triggering hormones that promote feelings of fullness and satisfaction.5 Your body also burns more calories digesting protein compared to fat or carbs.6


 

Guidelines for individualized protein intake

Taking into account the among keto and low-carb experts, we recommend a protein intake of 1.2-1.7 grams per kg of body weight for most people.Protein intake within this range has been shown to preserve muscle mass, improve body composition, and provide other health benefits in people who eat low-carb diets or higher-carb diets.7

In a few cases, even higher protein intake of up to 2.0 grams of protein per kg of body weight may be beneficial, at least temporarily.8 This would include people who are underweight or healing from illness, injury, or surgery and, in some cases, people who are very physically active (more on this in the exercise section below).

On the other hand, individuals who follow keto diets for therapeutic purposes – for instance, for management of certain cancers – may need to restrict protein intake to less than 1.0 gram per kg of body weight per day.9 Importantly, this must be done under strict medical supervision.

Follow these guidelines to customize your own protein intake.

woman satisfied

Use reference or ideal body weight if overweight

If you’re near your ideal body weight or very muscular, use your actual weight (in kilograms) to calculate your protein needs. However, if you’re overweight, it’s best to use your reference weight or ideal body weight in order to prevent overshooting your protein needs, which are based on the amount of lean mass you have.

You can use this calculator to determine your ideal body weight in kilograms, and then multiply this number by 1.2-1.7 to get your daily protein range.

Aim for at least 20 grams of protein at each meal

Research has suggested that your body needs about 20-30 grams of protein at each meal to ensure that amino acids get incorporated into your muscles.10 Therefore, it may be best to spread out your protein intake evenly among two or three feedings rather than consuming most of it at one meal – at least if you want to increase your muscle mass.

Can you eat too much protein in one meal? This is controversial, with surprisingly little research to answer the question. Two studies in 2009 showed that single meal protein levels of 20g or 30g maximally stimulate muscle growth.11 Adding more in a meal did not increase immediate muscle growth. For some, that meant anything above 30 grams in a single meal was “wasted.” But that is not what the studies showed. Since there are other potential benefits to protein intake beyond immediate muscle synthesis, these studies don’t prove the more protein is “wasted.” In addition, how does eating just once or twice per day affect protein usage? How do low carb diets change that? We don’t have answers to these questions, and therefore do not recommend limiting protein to no more that 30 grams per meal.

Older people and children have increased protein needs

Growing children have a higher RDA for protein than adults (0.95g/kg vs 0.8g/kg), which empirically makes sense given the higher growth rate.12 Then as we become young adults, our protein needs aren’t as high as children’s relative to our height and body weight. But as we approach old age, our needs increase again.

Health organizations in the US, European, and most other countries recommend a minimum daily intake of 0.8 grams of protein per kilogram for all adults aged 19 and older.13

However, several experts in protein research believe that people over 65 need a minimum of 1.2 grams per kg daily to counteract muscle loss and other age-related changes.14

For example, in a recent study of older women, consuming more than 1.1 gram of protein per kg every day was linked to a decreased risk of frailty, a condition marked by weakness, loss of strength, and other changes that often occur during the aging process.15

man with kettlebell

Resistance training increases your protein requirements

People who engage in weight lifting and other forms of resistance training likely need more protein than people of the same height and weight who are sedentary.16

If you perform strength training, aim for a protein intake at or near the top of your range, especially if your goal is gaining muscle. A total protein intake of up to about 1.6 g/kg/day may help increase muscle mass.17

However, keep in mind that even with rigorous training, there is a limit to how quickly you can increase muscle mass, regardless of how much protein you consume.

How much protein should I eat every day?

Getting the right amount of protein needn’t be complicated or stressful. Most of the time, you’ll end up within your target range by simply eating an amount that is satisfying and paying attention to when you begin to feel full.

Here are the amounts of food you need to eat to get 20-25 grams of protein:

  • 100 grams (3.5 ounces) of meat, poultry or fish (about the size of a deck of cards)
  • 4 large eggs
  • 240 grams (8 ounces) of plain Greek yogurt
  • 210 grams (7 ounces) of cottage cheese
  • 120 grams (4 ounces) of hard cheese (about the size of a fist)
  • 120 grams (4 ounces) of almonds, peanuts, or pumpkin seeds (about the size of a fist)

Other nuts, seeds, and vegetables provide a small amount of protein, roughly 2-6 grams per average serving.

20 g of protein in 4 ways
The image above shows 20 grams of protein in four different ways. Almonds, salmon, eggs and chicken thighs.

Below you’ll find examples of three different levels of daily protein intake using the same foods:

About 70 grams of protein

Breakfast plate 30 g cheese 2 eggs

Breakfast

2 eggs
30 g (1 oz) cheese

Serving suggestion
1 cup mushrooms
1 cup spinach

Lunch plate 85 g salmon

Lunch

85 g (3 oz) salmon

Serving suggestion
2 cups mixed salad
½ avocado
2 tbsp olive oil

Dinner plate 80 g chicken

Dinner

85 g (3 oz) chicken

Serving suggestion
1 cup cauliflower
2 tbsp butter

About 100 grams of protein

Breakfast plate 30 g cheese 2 eggs

Breakfast

2 eggs
30 g (1 oz) cheese

Serving suggestion
1 cup mushrooms
1 cup spinach

Lunch plate 100 g salmon

Lunch

130 g (4.5 oz) salmon

Serving suggestion
2 cups mixed salad
½ avocado
2 tbsp olive oil

Dinner plate 100 g chicken

Dinner

140 g (5 oz) chicken

Serving suggestion
1 cup cauliflower
2 tbsp butter

About 130 grams of protein

Breakfast plate 30 g cheese 3 eggs

Breakfast

3 eggs
30 g (1 oz) cheese

Serving suggestion
1 cup mushrooms
1 cup spinach

Lunch plate 150 g salmon

Lunch

150 g (5 oz) salmon

Serving suggestion
2 cups mixed salad
½ avocado
2 tbsp olive oil

Dinner plate 150 g chicken

Dinner

180 g (6 oz) chicken

Serving suggestion
1 cup cauliflower
2 tbsp butter

Tips for further personalization 18

  • Adjust the protein portions up or down as needed, but don’t be concerned about hitting an exact target. Remember, your ideal protein range is pretty broad, and you should feel completely free to vary the amount you eat by 30 grams – or even more – from day to day. If you are lower in protein one day, try to add extra the following day.
  • If you’re an intermittent faster, you may want to increase the protein portions at the two meals you eat somewhat. For instance, in the 70-gram example above, either eat larger portions of fish at lunch and chicken at dinner, or add hard-boiled eggs at lunch and have a piece of cheese after dinner.
  • If you eat one meal per day (OMAD) it may be a challenge to get adequate protein intake. Consider eating OMAD a few times per week, with higher protein intake on the other days. Or, if you prefer the consistency of OMAD every day, consider eating within a 2-hour time window. That allows you to eat your meal and still have time to snack on nuts, cheese, or meats to increase your protein.
  • Eat nuts and seeds at meals or as snacks. Keep in mind that they provide about 2-6 grams of protein per quarter cup or 30 grams (1 ounce). But beware, they contain some carbs, which can add up quickly and are also high in calories. Therefore, being cautious with nut intake is a good idea for most people, especially if you’re trying to lose weight.

Different experts’ views on protein intake 19

If you’re feeling overwhelmed or confused about how much protein you need on a keto or low-carb diet, you’re not alone. Protein intake can be a controversial topic in the low-carb world, and it’s very common to find conflicting information about this online and in books, especially with the growing popularity of this lifestyle. That’s why we’ve included our simple recommendations earlier in this guide, as a good guidelines for most people. However, if you’re interested in the different views among experts working in the field of low carb, read on for a summary.

One of the reasons is the lack of universal agreement among keto and low-carb experts about what’s optimal when it comes to protein intake:

  • Lower protein: Dr. Ron Rosedale recommends 1.0 gram of protein per kilogram (2.2 lbs) of lean mass on a keto diet to promote longevity. For a person who weighs 68 kg (150 lbs), this would be about 60-63 grams of protein per day, depending on body composition.
  • Higher protein: At the other end of the spectrum, Dr. Ted Naiman advocates high protein intake for people who follow low carb or keto, especially those interested in weight loss. His recommendation is to consume 1 gram of protein per 1 lb of lean mass. For the same 68-kg (150-lbs) person above, this would be about 130-140 grams of protein daily – more than double the amount Dr. Rosedale advises.
  • Moderate protein: Recommendations from most of the other experts fall somewhere in between these two. For instance, ketogenic researchers Drs. Steve Phinney and Jeff Volek recommend 1.5-1.75 grams of protein per kg of reference weight or “ideal” body weight for most individuals. For a 68-kg person, this is around 102-119 grams of protein per day.

Adding to the confusion, other doctors and scientists promote that protein restriction is a key to longevity, and therefore we should aim for less protein than even the RDA suggests. The general concern is that protein promotes growth, and as we age we need to prevent abnormal growth, such as cancer cells or amyloid plaques in the brain. While there is preliminary evidence in worms, rodents and other animals that protein restriction can promote longevity, data in humans, and specifically humans eating a low-carb diet, is lacking.20 Therefore, we feel it is far too premature to draw any conclusions about too much protein in a low carb diet, especially given the risks of eating too little protein as described in this guide.

 

Does protein adversely affect blood sugar?

One of the arguments made in favor of keeping protein on the lower end is that higher intakes may increase blood sugar and insulin levels. This is a somewhat common anecdotal report from our members and others with diabetes. However, there appears to be a disconnect between anecdotal concerns and published research.21 For instance, two studies showed a diet with 30% of calories from protein improved glycemic control.22 In fairness, it was compared to a higher carbohydrate diet, but none the less, the higher protein intake did not blunt the benefit from lowering carbs.

Another study found patients with type 2 diabetes eating a 50g protein meal had no significant increase in serum glucose concentration.23

In a recent presentation, Dr. Ben Bikman proposed that your body’s ability to regulate blood sugar and insulin after you eat protein is influenced mainly by your carb intake, as well as how metabolically healthy you are. Overall, he has observed that those who eat keto or very low carb aren’t affected by high protein intake the way people on high-carb diets are.

Therefore, although protein physiologically triggers a glucose and insulin response, this is unlikely to be a clinical concern for most people. At Diet Doctor, our ketogenic recipes are moderate rather than high in protein. If you find your blood glucose increases after eating a moderate protein low-carb meal, first make sure it is truly following low-carb guidelines without hidden carbs or sugars. If so, then you may want to temporarily decrease your protein intake to see if it makes a difference. However, we emphasize the temporary nature of this as getting an adequate amount of protein still remains a long-term priority.

A final word on protein

When consuming meals that contain enough fat and non-starchy vegetables and are based on whole foods, most people will find it difficult to go overboard with protein. Our advice? Aim for a moderate amount (1.2-1.7g/kg/day), spread it out as best you can over 2-3 meals, and focus on healthy low-carb meals you enjoy!

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Our top videos on protein

  1. Muscle, hormones, enzymes and other structures in your body are made up of 20 amino acids, the building blocks of protein. Every day, old proteins are broken down. Although most are recycled, a portion needs to replenished with new amino acids, 9 of which are essential, meaning your body can’t make them. These 9 amino acids must come from protein in your diet.

    International Journal for Vitamin and Nutrition Research 2011: Protein turnover, ureagenesis and gluconeogenesis [overview article; ungraded]

  2. The essential amino acids are named phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, and histidine.

    USDA.gov: Dietary Reference Intake [overview article; ungraded]

  3. American Journal of Clinical Nutrition 2015: Commonly consumed protein foods contribute to nutrient intake, diet quality, and nutrient adequacy [overview article; ungraded]

    Scientific Reports 2016: Essential amino acids: master regulators of nutrition and environmental footprint? [overview article, ungraded]

  4. Most people can probably build muscle well with a protein intake of no more than 1.6 g/kg/day:

    British Journal of Sports Medicine 2018: A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults [strong evidence]

  5. Advances in Nutrition 2015: Controversies surrounding high-protein diet intake: satiating effect and kidney and bone health [review of observational studies; weak evidence]

  6. Journal of the American College of Nutrition 2004: The effects of high protein diets on thermogenesis, satiety and weight loss: a critical review [systematic review of randomized trials; strong evidence]

  7. Low-carb diets:

    Peer J 2019: Low-carbohydrate diets differing in carbohydrate restriction improve cardiometabolic and anthropometric markers in healthy adults: a randomised clinical trial [moderate evidence]

    Diabetes Therapy 2018: Effectiveness and safety of a novel care model for the management of type 2 diabetes at 1 year: an open-label, non-randomized, controlled study [weak evidence]

    Moderate protein diets for weight loss:

    American Journal of Clinical Nutrition 2015: The role of protein in weight loss and maintenance [overview article; ungraded]

    Higher-carb diets:

    Nutrients 2018: Effects of a high-protein diet including whole eggs on muscle composition and indices of cardiometabolic health and systemic inflammation in older adults with overweight or obesity: a randomized controlled trial [moderate evidence]

    The American Journal of Clinical Nutrition 2017: The effects of dietary protein intake on appendicular lean mass and muscle function in elderly men: a 10-wk randomized controlled trial [moderate evidence]

    The Journal of Nutrition 2013: Normal protein intake is required for body weight loss and weight maintenance, and elevated protein intake for additional preservation of resting energy expenditure and fat free mass [randomized trial; moderate evidence]

    For metabolic functions:

    American Journal of Clinical Nutrition 2015: Defining meal requirements for protein to optimize metabolic roles of amino acids [overview article; ungraded]

  8. American Journal of Clinical Nutrition 2012: Appropriate protein provision in critical illness: a systematic and narrative review [review of observational studies; weak evidence]

  9. Redox Biology: Ketogenic diets as an adjuvant cancer therapy: History and potential mechanism [overview article; ungraded]

  10. The precise amount that can be absorbed and used depends on age, muscle mass, meal composition and other factors. However, in one study of both young and older adults, a very high-protein (90 grams) meal didn’t lead to greater muscle protein synthesis than a moderate-protein (30 grams) meal.

    Journal of the American Dietetic Society 2011: Moderating the portion size of a protein-rich meal improves anabolic efficiency in young and elderly [randomized trial; moderate evidence]

    This article is a thorough review and expert opinion on the subject:

    The American Journal of Clinical Nutrition: Defining meal requirements for protein to optimize metabolic roles of amino acids [scientific review and expert opinion; weak evidence]

  11. Journal of the American Dietitians Association 2009: A moderate serving of high-quality protein maximally stimulates skeletal muscle protein synthesis in young and elderly subjects [randomized trial; moderate evidence]

    American Journal of Clinical Nutrition 2009: Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men [randomized trial; moderate evidence]

  12. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids 2002: Dietary reference intakes: Macronutrients [overview article; ungraded]

  13. Journal of the American Dietetics Association 2002: Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein and amino acids [consensus guideline article; ungraded]

  14. NRC Research Press: Protein: A nutrient in focus [overview article; ungraded]

    Nutrients 2016: Protein consumption and the elderly: What is the optimal level of intake? [overview article; ungraded]

  15. European Journal of Nutrition 2019: Higher protein intake is associated with a lower likelihood of frailty among older women, Kuopio OSTPRE-Fracture Prevention Study [observational study; very weak evidence]

  16. Journal of Sports Science 2011: Dietary protein for athletes: from requirements to optimum adaptation [overview article; ungraded]

  17. British Journal of Sports Medicine 2018: A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults [strong evidence]

  18. This is based on opinion to help provide practical guidance for achieving protein goals. [very weak evidence]

  19. These are based on the beliefs of individual practitioners. [very weak evidence]

  20. Aging Cell 2012: Comparative and meta-analytic insights into life extension via dietary restriction

  21. The trials included in this review of RCTs did not restrict protein intake and showed significant improvement in blood glucose levels and metabolic health.

    BMJ Open Diabetes Research and Care: Systematic review and meta-analysis of dietary carbohydrate restriction in patients with type 2 diabetes [strong evidence]

  22. Diabetes 2004: Effect of a high-protein, low-carbohydrate diet on blood glucose control in people with type 2 diabetes [randomized trial; moderate evidence]

    American Jopurnal of Clinical Nutrition 2003: An increase in dietary protein improves the blood glucose response in persons with type 2 diabetes [randomized trial; moderate evidence]

  23. Journal of Clinical Endocrinology and Metabolism 2001: Effect of protein ingestion on the glucose appearance rate in people with type 2 diabetes [randomized trial; moderate evidence]