All About Protein

​Overall Recommendation ​

• ​Eat 3-5 meals daily with a few snacks (aim for 30-40g protein each time you eat)
• Focus on whole food sources, and supplement as needed.
  • A mix of animal and plant sources tends to be best, but sufficient protein can come from plant sources alone (see notes below for elaboration).

Protein timing(1,2,4,5)

• Typically splitting up between 3-5 meals and a few snacks is best
• ​Bedtime dose of casein may be beneficial as well, but if it interferes with sleep then don’t worry about (~40g)
• Yes, there is an ‘anabolic window’, but it’s not as crucial as most people believe
  • Often, people have had a meal within 3-5 hours of working out and so there’s still circulating AA (amino acids)
  • If you work out first thing in the morning, it may be a good idea to have some protein before
  • Getting protein within 3-5 hours of workout should be sufficient for most people, but MPS (muscle protein synthesis) is elevated for 24+ hours post-workout
  • Can be helpful to have a protein/carb mixed meal or shake after exercise to help replenish muscle glycogen (sugar/carb stored in the muscle for energy).​​

Protein quality(1,2,4,5,6)

• Protein should come mostly from whole foods, with priority given to animal proteins, particularly milk products
• If supplementing, best to supplement with whey protein isolate or hydrolyzed whey protein – the fewer ingredients the better
  • ​Whey – faster-digesting, more readily available for body to use
    • ​​Also, better at whole-body protein synthesis (MPS)
    • Absorbed at about 10g/hr
  • ​Casein – slower-digesting, longer MPS response (ideal for bedtime)
    • Better at whole-body suppression of muscle protein breakdown (MPB)
    • Absorbed at about 6g/hr
  • ​Milk Protein
    • ​Blend of whey & casein
    • Absorbed at about 3.5g/hr
  • Animal proteins typically utilized better/more easily than plant
    • ​​​Also, more likely to have all Essential AAs (20 amino acids, 9 essential, 6 conditionally non-essential)

BCAAs (4,7,8,9)

• Not really useful for anything performance related; even when used for “recovery”, evidence shows you’d be better off using EAAs (essential amino acids)
• They all use the same transporter, so taking BCAAs vs EAAs can cause interference in uptake
• You need all of the AAs to build muscle
• Some evidence that they can help with cognition and in certain disorders, but evidence is preliminary and limited
• Leucine is associated with a strong MPS response, but it works like a dimmer switch – more of it up to a point helps, but you still need all of the other AAs to build muscle, and you’ll be limited by AA you don’t have enough of
  • 3-4 oz meat, 3-5 eggs, 1-2 glasses of milk sufficient for leucine

​Plant Proteins (1,2,3) 

Plant proteins can work just as well as animal proteins for getting enough daily protein in a diet. There are a few main limitations, but these can be largely overcome as detailed below:

1. Low EAA and leucine content
   1. Eat different plants throughout the day
   2. Fortify with EAA supplements
2. Lower protein bioavailability
   1. Use processes that improve your body's ability to use plant protein, such as preparation, cooking, sprouting, soaking, and/or use of digestive enzymes
3. Lower protein content per serving
   1. Increase serving sizes of plant foods or isolated plant proteins

Muscle is very metabolically active (5,10,11,12,13)

• Energy expenditure of ~9-10 calories/lb of mm mass
  
• Biggest reserve of AAs for body to use and utilize
  
• Reserve for muscle glycogen – thus, can help to control blood sugar – the more muscle, the more room for energy storage and utilization

References:

1. Jäger R, et al. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr. 2017 Jun 20;14:20. doi: 10.1186/s12970-017-0177-8. PMID: 28642676; PMCID: PMC5477153.
   
2. Wu G. Dietary protein intake and human health. Food Funct. 2016 Mar;7(3):1251-65. doi: 10.1039/c5fo01530h. PMID: 26797090.
   
3. Nichele S, Phillips SM, Boaventura BCB. Plant-based food patterns to stimulate muscle protein synthesis and support muscle mass in humans: a narrative review. Appl Physiol Nutr Metab. 2022 Jul 1;47(7):700-710. doi: 10.1139/apnm-2021-0806. Epub 2022 May 4. PMID: 35508011.
   
4. 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 Feb 27;15:10. doi: 10.1186/s12970-018-0215-1. PMID: 29497353; PMCID: PMC5828430.
   
5. Morton RW, McGlory C, Phillips SM. Nutritional interventions to augment resistance training-induced skeletal muscle hypertrophy. Front Physiol. 2015 Sep 3;6:245. doi: 10.3389/fphys.2015.00245. PMID: 26388782; PMCID: PMC4558471.
   
6. Bilsborough S, Mann N. A review of issues of dietary protein intake in humans. Int J Sport Nutr Exerc Metab. 2006 Apr;16(2):129-52. doi: 10.1123/ijsnem.16.2.129. PMID: 16779921.
   
7. Wolfe RR. Branched-chain amino acids and muscle protein synthesis in humans: myth or reality? J Int Soc Sports Nutr. 2017 Aug 22;14:30. doi: 10.1186/s12970-017-0184-9. PMID: 28852372; PMCID: PMC5568273.
   
8. Kollias, Helen. “What Are BCAAs–and Are They Worth It?” Precision Nutrition, 29 Oct. 2021, www.precisionnutrition.com/what-are-bcaas-benefits.
   
9. Biologydictionary.net Editors. "Branched Chain Amino Acids." Biology Dictionary, Biologydictionary.net, 08 Jan. 2020, https://biologydictionary.net/branched-chain-amino-acids/.
   
10. Chadt A, Al-Hasani H. Glucose transporters in adipose tissue, liver, and skeletal muscle in metabolic health and disease. Pflugers Arch. 2020 Sep;472(9):1273-1298. doi: 10.1007/s00424-020-02417-x. Epub 2020 Jun 26. PMID: 32591906; PMCID: PMC7462924.
    
11. Argilés JM, Campos N, Lopez-Pedrosa JM, Rueda R, Rodriguez-Mañas L. Skeletal Muscle Regulates Metabolism via Interorgan Crosstalk: Roles in Health and Disease. J Am Med Dir Assoc. 2016 Sep 1;17(9):789-96. doi: 10.1016/j.jamda.2016.04.019. Epub 2016 Jun 17. PMID: 27324808.
    
12. Kim G, Kim JH. Impact of Skeletal Muscle Mass on Metabolic Health. Endocrinol Metab (Seoul). 2020 Mar;35(1):1-6. doi: 10.3803/EnM.2020.35.1.1. PMID: 32207258; PMCID: PMC7090295.
    
13. Nuckols, Greg. “How Many Additional Calories Does Each Pound of Muscle Burn? .” Stronger by Science, 14 June 2023, www.strongerbyscience.com/calories-muscle-burn/.