Perfect your protein

A protein guide brought to you by Dr. Peter Attia.

Everything you need to know about protein, from our Chief Science Officer.

This protein guide is brought to you by our Chief Science Officer, Peter Attia.

Peter Attia, MD, is the founder of Early Medical, a medical practice that applies the principles of Medicine 3.0 to patients with the goal of simultaneously lengthening their lifespan and increasing their healthspan.

He is the host of The Drive, one of the most popular podcasts covering the topics of health and medicine. He is also the author of the #1 New York Times Bestseller, Outlive: The Science and Art of Longevity.

Dr. Attia received his medical degree from the Stanford University School of Medicine and trained for five years at the Johns Hopkins Hospital in general surgery.

Your ultimate protein guide.

The role of protein in our bodies and its building blocks.

To understand how protein works, it is helpful to recognize that there are three primary macronutrients: carbohydrates, fats, and proteins.

Carbohydrates are our main source of quick energy, broken down into glucose during digestion to fuel our cells. Any excess glucose is stored for later use as glycogen or fat.

Fats, on the other hand, provide both energy through a slower-burning process and serve as crucial building blocks for hormones and cell membranes. They are essential, but when over-consumed can easily lead to fat storage and weight gain.

Proteins are complex structures made up of long chains of amino acids. The human body uses 20 different amino acids to create proteins, but nine of these are 'essential' because we are not able to produce them ourselves and must obtain them through food. Without these amino acids from food, we could not survive. When we eat protein, our bodies break it down into individual amino acids, which are then reassembled in specific sequences to form the various proteins our bodies need like muscle, skin, and hair.

Protein’s importance for health and body composition.

Protein is a vital nutrient for the human body, supporting a wide range of functions that include building and repairing tissues like muscle, facilitating cellular processes, aiding metabolic reactions, and boosting immune function. Its primary role lies in providing essential amino acids that our bodies cannot produce on their own, which are critical for tissue growth and repair.

Adequate protein intake is especially critical for two reasons: first, it helps build and preserve muscle mass now and as we age. Second, it plays a vital role in managing metabolic health and preventing excess body fat accumulation, reducing the risk of various diseases.

Optimal daily protein intake.

Research indicates that humans require much more than the US RDA (recommended daily allowance) for protein–which is 0.8g per kg of body weight–to achieve optimal health and prevent muscle loss as we age. The RDA underestimates the need for protein due its basis in notoriously unreliable nitrogen balance studies. Additionally, the RDA guideline represents only the minimum amount needed to merely avoid malnutrition. For optimal health and muscle maintenance, consuming 2-3 times that amount, or around 0.8-1 gram of protein per pound of body weight, is recommended. This higher intake promotes lean tissue growth and helps prevent excess body fat accumulation.

Common myths about the dangers of high protein intake.

While there might be a theoretical upper limit for safe protein intake, the notion that consuming too much protein is harmful lacks any concrete scientific research and evidence. There may be an upper limit of protein intake that is safe, but it would be so high that it has not yet been discovered in human nutritional studies. Consequently, protein consumption within the range of 0.8 to 1 gram per pound of body weight is generally considered only beneficial. Outside from avoiding overconsumption of calories in general, one does not need to worry about overconsumption of protein on a practical basis.

The role of protein in both building muscle and reducing body fat.

High protein consumption not only supports muscle growth and preservation but also contributes to fat loss. To achieve fat loss, one must create a calorie deficit by expending more calories than she consumes. Protein is an effective tool for creating a calorie deficit in two key ways:

Increased Satiety: Protein promotes feelings of fullness, leading to reduced calorie intake compared to diets lower in protein. This fact is supported by the Protein Leverage Hypothesis, which suggests a natural drive to consume enough protein. This natural drive to consume enough protein can lead to the overconsumption of calories if one eats foods that are low in protein.
Higher Thermogenesis: Protein digestion requires more energy than that of fats or carbohydrates–increasing overall calorie expenditure. This means the net energy gain from protein is lower than its nominal value, contributing to a calorie deficit. Compared to the 0-3% for fat and 5-10% for carbohydrates, protein's thermogenic effect of 20-30% is significantly higher. This means that if you consume 100 calories of protein, your body only nets ~75 calories after digestion of that protein.

Is all protein created equal in terms of quality?

The effectiveness of protein consumption is influenced by its bioavailability and its amino acid profile, measured by the PDCAAS (Protein Digestibility Corrected Amino Acid Score). A perfect score of 1.0 indicates complete digestibility and an optimal amino acid profile for humans.

Animal-based proteins typically have higher PDCAAS values compared to plant-based proteins. Plant-based proteins are often encased in fiber or contain compounds that hinder digestion, and they often do not provide the ideal amino acid composition for building human tissues like muscle and skin.

Vegetarians and vegans relying on plant-based protein sources need to consume higher amounts of protein to compensate for lower digestibility and less optimal amino acid profiles. This doesn't imply a judgment on dietary choices, but rather highlights the need for increased protein intake and careful selection of plant sources to ensure adequate nutrition.

For reference, some PDCAAS figures are: 1.0 for Milk Protein, 1.0 for Egg White, 0.92 for Beef, 0.8 for Pea protein isolate, 0.6 for Chickpeas, and 0.5 for Peanuts.

Concise summary of how to optimize our protein consumption.

Achieving optimal protein consumption involves focusing on three key factors. First, aim to consume 0.8-1.0 grams of protein per pound of body weight each day. Second, be mindful of overall calorie intake, as consuming too many calories, even from protein, can hinder fat loss goals. Finally, prioritize high-quality protein sources with a high PDCAAS (Protein Digestibility Corrected Amino Acid Score) to ensure the body receives essential amino acids in the most effective way possible. By focusing on these three principles, protein consumption can be optimized for long-term health and performance.

With 28g of protein, 150 calories, and a perfect PDCAAS score of 1.0, consuming David is an exceptional way to meet these nutritional goals. Crafted to provide high-quality protein in a low-calorie package, David supports muscle growth and fat loss.

1. Wolfe RR, Cifelli AM, Kostas G, Kim IY. Optimizing protein intake in adults: Interpretation and application of the recommended dietary allowance compared with the Acceptable Macronutrient Distribution Range. Adv Nutr. 2017;8(2):266-275. https://doi.org/10.3945/an.116.013821

2. Houston DK, Nicklas BJ, Ding J, et al. Dietary protein intake is associated with lean mass change in older, community-dwelling adults: the Health, Aging, and Body Composition (Health ABC) Study. Am J Clin Nutr. 2008;87(1):150-155. https://doi.org/10.1093/ajcn/87.1.150

3. Wu G. Dietary protein intake and human health. Food Funct. 2016;7(3):1251-1265. https://doi.org/10.1039/c5fo01530h

4. Rhee CM, Ahmadi SF, Kovesdy CP, Kalantar-Zadeh K. Low-protein diet for conservative management of chronic kidney disease: a systematic review and meta-analysis of controlled trials. J Cachexia Sarcopenia Muscle. 2018;9(2):235-245. https://doi.org/10.1002/jcsm.12264

5. Schaafsma G. Advantages and limitations of the protein digestibility-corrected amino acid score (PDCAAS) as a method for evaluating protein quality in human diets. Br J Nutr. 2012;108 Suppl 2(S2):S333-6. https://doi.org/10.1017/S0007114512002541

6. Phillips SM, Paddon-Jones D, Layman DK. Optimizing adult protein intake during catabolic health conditions. Adv Nutr. 2020;11(4):S1058-S1069. https://doi.org/10.1093/advances/nmaa047

7. Matsuoka R, Kurihara H, Nishijima N, Oda Y, Handa A. Egg white hydrolysate retains the nutritional value of proteins and is quickly absorbed in rats. ScientificWorldJournal. 2019;2019:5475302. https://doi.org/10.1155/2019/5475302

8. Pennings B, Groen B, de Lange A, et al. Amino acid absorption and subsequent muscle protein accretion following graded intakes of whey protein in elderly men. Am J Physiol Endocrinol Metab. 2012;302(8):E992-9. https://doi.org/10.1152/ajpendo.00517.2011

9. Berrazaga I, Micard V, Gueugneau M, Walrand S. The role of the anabolic properties of plant- versus animal-based protein sources in supporting muscle mass maintenance: A critical review. Nutrients. 2019;11(8):1825. https://doi.org/10.3390/nu11081825

10. Schoenfeld BJ, Aragon AA. How much protein can the body use in a single meal for muscle-building? Implications for daily protein distribution. J Int Soc Sports Nutr. 2018;15:10. https://doi.org/10.1186/s12970-018-0215-1

11. Cuthbertson D, Smith K, Babraj J, et al. Anabolic signaling deficits underlie amino acid resistance of wasting, aging muscle. FASEB J. 2005;19(3):422-424. https://doi.org/10.1096/fj.04-2640fje

12. Pinckaers PJ, Domić J, Petrick HL, et al. Higher muscle protein synthesis rates following ingestion of an omnivorous meal compared with an isocaloric and isonitrogenous vegan meal in healthy, older adults. J Nutr. 2024;154(7):2120-2132. https://doi.org/10.1016/j.tjnut.2023.11.004

13. Trommelen J, van Lieshout GAA, Nyakayiru J, et al. The anabolic response to protein ingestion during recovery from exercise has no upper limit in magnitude and duration in vivo in humans. Cell Rep Med. 2023;4(12):101324. https://doi.org/10.1016/j.xcrm.2023.101324

14. Oliveira CLP, Boulé NG, Sharma AM, et al. A high-protein total diet replacement increases energy expenditure and leads to negative fat balance in healthy, normal-weight adults. Am J Clin Nutr. 2021;113(2):476-487. https://doi.org/10.1093/ajcn/nqaa283

15. Batterham RL, Heffron H, Kapoor S, et al. Critical role for peptide YY in protein-mediated satiation and body-weight regulation. Cell Metab. 2006;4(3):223-233. https://doi.org/10.1016/j.cmet.2006.08.001

16. Santesso N, Akl EA, Bianchi M, et al. Effects of higher- versus lower-protein diets on health outcomes: a systematic review and meta-analysis. Eur J Clin Nutr. 2012;66(7):780-788. https://doi.org/10.1038/ejcn.2012.37

17. Zapata RC, Singh A, Pezeshki A, Avirineni BS, Patra S, Chelikani PK. Low-protein diets with fixed carbohydrate content promote hyperphagia and sympathetically mediated increase in energy expenditure. Mol Nutr Food Res. 2019;63(21):e1900088. https://doi.org/10.1002/mnfr.201900088

18. Qi XX, Shen P. Associations of dietary protein intake with all-cause, cardiovascular disease, and cancer mortality: A systematic review and meta-analysis of cohort studies. Nutr Metab Cardiovasc Dis. 2020;30(7):1094-1105. https://doi.org/10.1016/j.numecd.2020.03.008

The role of protein in our bodies and its building blocks.

To understand how protein works, it is helpful to recognize that there are three primary macronutrients: carbohydrates, fats, and proteins.

Carbohydrates are our main source of quick energy, broken down into glucose during digestion to fuel our cells. Any excess glucose is stored for later use as glycogen or fat.

The role of protein in our bodies and its building blocks.

To understand how protein works, it is helpful to recognize that there are three primary macronutrients: carbohydrates, fats, and proteins.

Carbohydrates are our main source of quick energy, broken down into glucose during digestion to fuel our cells. Any excess glucose is stored for later use as glycogen or fat.

Protein’s importance for health and body composition.

Optimal daily protein intake.

Common myths about the dangers of high protein intake.

The role of protein in both building muscle and reducing body fat.

Increased Satiety: Protein promotes feelings of fullness, leading to reduced calorie intake compared to diets lower in protein. This fact is supported by the Protein Leverage Hypothesis, which suggests a natural drive to consume enough protein. This natural drive to consume enough protein can lead to the overconsumption of calories if one eats foods that are low in protein.
Higher Thermogenesis: Protein digestion requires more energy than that of fats or carbohydrates–increasing overall calorie expenditure. This means the net energy gain from protein is lower than its nominal value, contributing to a calorie deficit. Compared to the 0-3% for fat and 5-10% for carbohydrates, protein's thermogenic effect of 20-30% is significantly higher. This means that if you consume 100 calories of protein, your body only nets ~75 calories after digestion of that protein.

Is all protein created equal in terms of quality?

For reference, some PDCAAS figures are: 1.0 for Milk Protein, 1.0 for Egg White, 0.92 for Beef, 0.8 for Pea protein isolate, 0.6 for Chickpeas, and 0.5 for Peanuts.

Concise summary of how to optimize our protein consumption.

3. Wu G. Dietary protein intake and human health. Food Funct. 2016;7(3):1251-1265. https://doi.org/10.1039/c5fo01530h

6. Phillips SM, Paddon-Jones D, Layman DK. Optimizing adult protein intake during catabolic health conditions. Adv Nutr. 2020;11(4):S1058-S1069. https://doi.org/10.1093/advances/nmaa047

11. Cuthbertson D, Smith K, Babraj J, et al. Anabolic signaling deficits underlie amino acid resistance of wasting, aging muscle. FASEB J. 2005;19(3):422-424. https://doi.org/10.1096/fj.04-2640fje

The role of protein in our bodies and its building blocks.

To understand how protein works, it is helpful to recognize that there are three primary macronutrients: carbohydrates, fats, and proteins.

Carbohydrates are our main source of quick energy, broken down into glucose during digestion to fuel our cells. Any excess glucose is stored for later use as glycogen or fat.

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