#076 Building Muscle with Resistance Exercise and Reassessing Protein Intake | Stuart Phillips, PhD
Dr. Stuart Phillips, Professor of Kinesiology at McMaster University, discusses the critical role of muscle mass for longevity, optimal protein intake (beyond the RDA), and how exercise and nutrition combat age-related muscle loss. He also covers surprising anti-catabolic factors like omega-3 and heat stress.
Deep Dive Analysis
15 Topic Outline
Introduction to Muscle Mass and Longevity
Sarcopenia, Muscle Reserve, and Disability Threshold
Recommended Dietary Allowance (RDA) vs. Optimal Protein Intake
Caloric Restriction, Protein Restriction, and Catabolic Crises
Practical Tips for Protein Intake and Timing
Protein Quality: Animal vs. Plant-Based Proteins
Leucine Supplementation and Anabolic Resistance
Optimal Types and Frequency of Exercise
Mechanisms of Muscle Protein Synthesis and Breakdown
Hormonal Responses to Exercise: Testosterone and Growth Hormone
Mental Health Benefits of Exercise
Anti-Catabolic Effects of Heat Stress and Heat Shock Proteins
Molecular Causes of Sarcopenia
Anti-Catabolic Effects of Omega-3 Fatty Acids
Creatine Monohydrate for Muscle and Brain Health
5 Key Concepts
Catabolic Crisis
These are punctuated events of disuse and disease, such as hospitalization or severe illness, that lead to a rapid and precipitous decline in muscle mass. For older adults, these crises can accelerate age-related muscle loss, making it difficult to recover and potentially crossing a disability threshold.
Muscle Reserve
Similar to building bone mass, the concept of muscle reserve refers to accumulating and maintaining a higher level of muscle mass when younger. This higher baseline provides a buffer against the inevitable age-related muscle loss (sarcopenia) and helps mitigate the impact of catabolic crises later in life.
Protein Turnover
This is the continuous process within the body where existing proteins, particularly in muscle, are broken down and new proteins are synthesized. Physical exercise, including resistance training, accelerates this turnover, requiring increased protein intake to support repair and growth.
Anabolic Resistance
A phenomenon observed primarily in older adults where their muscles become less responsive to anabolic stimuli like protein intake or resistance exercise. This means older individuals require higher doses of protein or more intense exercise to achieve the same muscle protein synthesis response as younger individuals.
Heat Shock Proteins (HSPs)
These are a group of proteins produced by cells in response to various stressors, including heat (e.g., sauna exposure). HSPs act as 'chaperones,' helping other proteins maintain their proper folded structure and preventing misfolding, which can be beneficial in alleviating muscle atrophy, particularly during disuse.
14 Questions Answered
Muscle mass is critical for health, correlating inversely with mortality and being a key component of the frailty index. It enables essential activities of daily living, and its preservation as we age helps maintain strength, mobility, and overall quality of life.
The current RDA of 0.8 grams of protein per kilogram body weight per day is considered a minimal intake to prevent deficiency, not an optimal intake. Many experts, including Dr. Phillips, suggest a minimum closer to 1.2 g/kg/day for general health and higher for active or older individuals.
For physically active younger individuals aiming for hypertrophy, an intake of 1.6 grams of protein per kilogram body weight per day is recommended. Older adults, due to anabolic resistance, could also benefit from intakes up to 1.6 g/kg/day to support muscle mass and lean mass.
For most individuals, the total amount of protein consumed over the day is more important than precise timing around exercise. While elite athletes might see small benefits from even protein distribution, for most people, it's not a major factor compared to overall daily intake and consistent exercise.
Resistance training is the primary driver of muscle hypertrophy and strength gains, providing the vast majority of benefits. Protein intake acts as a 'thin layer on top,' offering additional, albeit smaller, incremental gains.
Leucine, one of the essential branched-chain amino acids, acts as a potent signal that 'turns on' the process of making new muscle proteins, primarily by activating the mTOR pathway. It's like a dimmer switch, initiating and increasing the rate of protein synthesis.
While animal proteins generally have a higher essential amino acid content, processing methods like cooking, sprouting, and fermentation can improve the bioavailability and quality of plant proteins. By consuming a slightly higher quantity or a variety of plant proteins, or using isolated plant protein supplements, it is possible to achieve sufficient essential amino acid intake for muscle protein synthesis.
Leucine supplementation can improve muscle protein synthesis response, especially with smaller protein doses or in older individuals, but it tastes bitter. BCAA supplements are largely considered ineffective if one is already consuming a high-protein diet, as the benefit comes primarily from leucine, which is abundant in quality proteins.
Anabolic resistance in older adults is partly driven by inactivity, as abrupt sedentarism can increase it. It may also involve aspects of vascular insulin resistance, where blood flow to muscles becomes less sensitive, reducing the delivery of nutrients needed for protein synthesis.
Most guidelines recommend at least two times per week of strengthening activities, with 30-45 minutes duration per session. Increasing frequency to three or four times a week can provide additional benefits, but the biggest impact comes from consistently moving from no activity to some activity.
Research indicates that the transient, normal fluctuations in testosterone and growth hormone following exercise do not significantly drive muscle protein synthesis or hypertrophy in adults. While supraphysiological doses (e.g., anabolic steroids) can increase muscle mass, normal physiological variations have a minimal impact on muscle growth.
Yes, heat exposure from sources like saunas can induce a thermal stress response that activates heat shock proteins (HSPs). These proteins help prevent misfolding of other proteins, potentially alleviating muscle atrophy, especially during periods of disuse, and may offer synergistic benefits with exercise.
Studies suggest that high-dose omega-3 fatty acid supplementation can have an anti-catabolic effect, helping to mitigate muscle atrophy, particularly during periods of disuse or in older populations. It can help reduce chronic low-grade inflammation, which is problematic for muscle health.
Creatine monohydrate is a well-studied supplement with a strong safety profile over 40 years of use, showing mild but consistent benefits for muscle growth and strength. Emerging evidence also suggests cognitive benefits, making it potentially useful for both younger and older individuals, even those not highly physically active.
32 Actionable Insights
1. Follow Exercise Guidelines
Aim for 150 minutes of moderate to vigorous exercise and two days of strengthening activities per week to gain an average of four extra years of life and extend your health span.
2. Engage in Resistance Exercise
Even very old individuals (90-99 years old) can significantly improve gait speed and strength through resistance exercise, which is crucial for maintaining function and preventing decline.
3. Optimize Protein Intake
Aim for a minimum of 1.2 grams of protein per kilogram of body weight per day, and potentially up to 1.6 g/kg for athletes and older adults, as the current RDA (0.8 g/kg) is considered a minimal intake, not optimal for muscle support, especially with age.
4. Avoid Disuse and Bed Rest
Periods of disuse, such as bed rest during hospitalization or prolonged inactivity, dramatically accelerate muscle loss, especially in older adults, making recovery difficult and leading to a steeper decline.
5. Stay Active to Combat Resistance
Being physically active, including both aerobic and resistance exercise, is crucial for maintaining vascular insulin sensitivity and combating age-related anabolic resistance, which makes muscles less responsive to protein.
6. Quit Smoking for Health
Giving up smoking is a crucial step for improving health and extending lifespan, as it is a major factor in shortened lifespan and poor quality of life.
7. Maintain Healthy Body Weight
Strive to maintain a healthy body weight, avoiding excessive weight gain, as this is a fundamental step towards aging well and overall health.
8. Preserve Muscle for Health
Muscle mass, a highly hydrated tissue, is critical for overall health, especially as one ages, and its preservation is vital.
9. Prevent Frailty with Muscle
Maintaining muscle mass is critical for health and is an important component of the frailty index, which is a strong predictor of mortality in older adults.
10. Manage Chronic Inflammation
Control chronic low-grade inflammation, as it contributes to anabolic resistance and can hinder the effectiveness of nutritional and exercise interventions for muscle health.
11. Resistance Train Regularly
Perform resistance training at least twice a week for 30-45 minutes, aiming for high levels of effort until fatigue, as this is a major driver of strength and muscle gains, with three times a week offering even greater benefits.
12. Supplement Omega-3s
Supplementing with high-dose omega-3 fatty acids can be anti-catabolic, helping to mitigate muscle atrophy during disuse and aiding quicker recovery, particularly beneficial for older populations.
13. Supplement Vitamin D
Supplement with Vitamin D, especially in winter months or northern latitudes, due to widespread deficiency and its crucial role as a steroid hormone regulating numerous genes beyond bone health.
14. Consider Creatine Monohydrate Supplementation
Creatine monohydrate is a safe and effective supplement for muscle growth and cognitive performance, even for those not physically active, with a recommended dose of 4-5 grams per day.
15. Build Muscle Reserves Early
Accumulate muscle mass through concerted resistance exercise in your younger years (30s-70s) to create a higher plateau, which helps buffer against age-related muscle loss and functional decline.
16. Prioritize Leucine Intake
Leucine, an essential branched-chain amino acid, acts as a potent trigger for muscle protein synthesis, and older individuals may require more leucine or higher quality protein to stimulate this process effectively.
17. Boost Older Adult Breakfast Protein
Older adults, especially women, should increase protein intake at breakfast with nutrient-dense sources like Greek yogurt or eggs to achieve a more even protein distribution throughout the day.
18. Total Protein Trumps Timing
For most people, the total daily protein intake is more important than precise timing; however, elite athletes may benefit from even distribution of protein throughout the day.
19. Follow 3 R’s for Recovery
After exercise, prioritize recovery by rehydrating with fluids, refueling with carbohydrates, and repairing muscles with protein, as these macronutrients are the primary drivers of the restorative process.
20. Eat Well 80% of Time
Pay attention to what you eat 80% of the time, focusing on less red meat, more fish, and fewer refined carbohydrates, allowing for occasional indulgences.
21. Reduce Alcohol Intake
Reduce alcohol consumption to improve overall health, as excessive drinking negatively impacts longevity and well-being.
22. Fast Before Bedtime
Not eating two to three hours before bed can be beneficial for most people, as insulin sensitivity is lower in the evening, allowing for a period of digestive rest.
23. Increase Protein in Deficit
When in a caloric deficit, consider increasing protein intake to help counteract the catabolic effects on muscle, as calorie deficits can accelerate muscle breakdown.
24. Enhance Plant Protein Absorption
Cooking, sprouting, and fermentation of plant-based proteins like beans and legumes can liberate proteins and reduce anti-nutritional effects, making them more bioavailable and closer in quality to animal proteins.
25. Begin with Bodyweight Exercises
You don’t need a gym to do resistance workouts; start with bodyweight exercises like air squats or wall push-ups to overcome barriers and initiate physical activity.
26. Use Sauna for Muscle Health
Regular sauna use or heat exposure can alleviate muscle atrophy by activating heat shock proteins, which help prevent protein misfolding and support muscle health, potentially synergizing with exercise benefits.
27. Sauna for Mental Well-being
Sauna use can improve mental well-being, including reducing anxiety and depressive symptoms, with effects comparable to some pharmaceutical interventions.
28. Consider Protein Supplements
If unable to meet protein needs through whole foods, protein supplements are a convenient and useful option, especially for older adults with reduced appetite or difficulty chewing.
29. Avoid Testosterone Boosters
Testosterone-boosting supplements are generally ineffective and a waste of money; focus on resistance training instead, as normal fluctuations in testosterone do not significantly drive muscle protein synthesis.
30. Avoid BCAA Supplements
Branch chain amino acid (BCAA) supplements are largely ineffective because only leucine is the important component for muscle protein synthesis, and if you’re already consuming a high-protein diet, they are redundant.
31. Caution with Exogenous Hormones
Be cautious with exogenous hormones like steroids and growth hormone, as their super-physiologic levels can lead to uncontrolled growth and potentially increase cancer risk, despite their muscle-building effects.
32. Leucine for Older Adults
For older individuals struggling to consume enough protein, supplementing with 3-4 grams of leucine per meal can enhance muscle protein synthesis, mimicking the effect of a larger protein dose.
7 Key Quotes
Carbohydrates and fats, that's fuel. You put that in and you burn it or we store it... But protein is something that when you ingest it, your body has to use it.
Stuart Phillips
I've stopped trying to fight too much against this because I would actually be happy if they just changed the name from recommended dietary allowance to minimal dietary intake.
Stuart Phillips
You get most of the benefit from just going to the gym, and then the protein effect is a thin layer on top.
Stuart Phillips
There's a great Instagram meme where I see a guy in a pool, it's raining, and he's drinking water. So it's sort of like that's where the branch chains are. I'm like, you're surrounded by good stuff, the branch chains are probably not a big deal.
Stuart Phillips
The biggest reduction in risk, bar none, is always going from nothing to doing something.
Stuart Phillips
If it sounds too good to be true, it probably is. If it's too good to be true, it's probably banned or you need a big prescription for it. There may be some exceptions as rule number three, but there are very few.
Stuart Phillips
The benefits of exercise never stop. I mean, it's almost embarrassing to talk about how good it is for you.
Stuart Phillips
2 Protocols
Optimal Protein Intake Strategy
Stuart Phillips- Aim for a minimum daily protein intake of 1.2 grams per kilogram body weight.
- Increase protein intake up to 1.6 grams per kilogram body weight per day if physically active or an older adult.
- Distribute protein intake relatively evenly throughout the day, especially for older individuals, rather than concentrating most consumption at dinner.
- Prioritize high-quality protein sources (e.g., animal products) or consume slightly more lower-quality plant proteins to ensure adequate essential amino acid intake.
Effective Resistance Training Regimen
Stuart Phillips- Engage in resistance training at least two times per week, with a target duration of 30 to 45 minutes per session.
- Focus on compound exercises that work multiple muscle groups, such as squats/leg presses, bench presses, and shoulder presses.
- Perform exercises with high levels of effort, lifting until you feel fatigued at the end of your sets, rather than strictly adhering to a percentage of your maximal lift.
- Allow for adequate recovery between workouts, especially if training different muscle groups on consecutive days, to facilitate muscle repair and adaptation.