Protein is getting a lot of air-time in the nutrition and well-being space at the moment and I wanted to lay it all out for you guys as to why. Gone are the days of weight-watchers and focusing solely on calories for weight-loss and health. Instead the focus has shifted, and rightly so, to the macronutrient profile of your meals (how much protein, carbohydrates and fats are on your plate) and ensuring the basis of your meals are whole, unprocessed foods. Weight-watcher bars are certainly a thing of the past!
Why is protein important?
Protein is a fundamental component of our diet, and along with fat, is essential to life. It’s used for both fuel and structure; so the growth, repair, and maintenance of all our tissues and organs. Like everything in life, our bodies thrive in a state of homeostasis, or balance. And to maintain this balance you have numerous internal checks and balances to keep everything in line. This is where the enzyme mTOR comes in.
What is mTOR?
mTOR plays a pivotal role in regulating cell growth, proliferation, and survival. It is part of a larger complex known as the mTOR complex, which is divided into two distinct phases: mTORC1 and mTORC2. mTORC1, is the most widely studied and is very sensitive to insulin and amino acids(c).
Confused? It’s okay, its’ not a test! Basically, any time you eat you activate mTOR.
“In simple terms, mTOR exists in almost every cell, where it controls a host of metabolic functions,” says writer David Whiteside on ThePaleoDiet.com. “It monitors numerous environmental cues, including carbohydrate and amino-acid concentrations and several growth-factor hormones. It constantly balances all these against current needs, surpluses, and deficits.”(a)
To understand mTOR, it's helpful to know about its opposite, autophagy. While mTOR is anabolic, promoting cell growth and proliferation, autophagy is catabolic, breaking down and recycling cellular components. Activating mTOR turns off autophagy and vice versa. Checks and balances. Homeostasis.
“When we eat carbohydrates or protein, insulin is secreted, and the increased insulin levels, or even just the amino acids from the breakdown of ingested protein, activate the mTOR pathway,” says Jason Fung, MD, in The Complete Guide to Fasting.
So when you eat, mTOR is activated, and on the other hand, when you restrict protein and calories, like during intermittent fasting, the opposite happens – you shut down mTOR and activate autophagy. Scientists are still learning how mTOR is connected to longevity and aging(d). But what we do know is that mTOR over-activation or dysregulation is linked to various metabolic diseases, cancers, and neurodegenerative disorders(e).
Creating the right balance between mTOR and autophagy is critical for overall health. Researchers see huge potential in this balance being helpful with a variety of diseases including neurodegenerative diseases, diabetes and cancer(f).
Why 30gms of protein per meal?
But why do we see 30gms of protein per meal recommended all over the place? Why is this a bit of a magic number? There are two main reasons:
Muscle mass and mTOR activation: Research suggests that one of the main ways to stimulate mTOR is by eating 25gms of protein every two hours(b). Additionally, 30gms is what triggers an amino acid response in your muscles that encourages them to grow stronger. In this particular study, researchers found that periodic doses of 30gms of protein cycled throughout the day was the most efficient way to build muscle.
Satiety and metabolic properties: Protein is known for its high satiety factor, meaning it helps you feel full longer. Consuming larger amounts of protein can aid in weight management by reducing overall calorie intake. Additionally, protein has a higher thermic effect compared to fats and carbohydrates, meaning the body burns more calories digesting and metabolising protein.
So, in conclusion, to age powerfully, function at our best and keep diseases at bay, we want to balance autophagy and mTOR to get the benefits of both.
How to balance autophagy and mTOR?
1. Stop snacking
According to Fung in The Complete Guide to Fasting, “the constant intake of food, such as snacking throughout the day, suppresses autophagy.”
This is because every time you eat, you trigger insulin. This hormone activates mTOR and shuts down fat burning. In other words, you’ll never get the benefits of autophagy if you’re constantly snacking.
Breaking this habit can be challenging. However one simple trick is to focus on your breakfast first. Just change your breakfast to a high protein (30-40gms) and limit the carbohydrates and I promise you’ll find you won’t be reaching for morning tea or even afternoon tea. You simply won’t feel like it!
2. Do an overnight fast
A simple way of getting the benefits of both mTOR and autophagy is to do an overnight fast. Although autophagy technically isn’t triggered until around 17 hours of fasting, there are still substantial benefits of a 12 – 14 hour fasted window. These include improved insulin sensitivity, reduced inflammation, enhanced fat metabolism and cognitive benefits with the production of ketones.
To create a fasting window, you’ll have a balanced dinner at around 5pm or close the kitchen around 3-4 hours before bed. Break your fast the following morning at around 9 or 10am with a high protein meal and voila! You’ve created a 12-14 hour overnight fast. If you’re new to fasting this might be enough for a while, if fasting is old-hat for you, then add in an 18 – 20 hour stretch every now and then.
3. Prioritise protein:
We’ve already discussed extensively how protein activates mTOR. Prioritise protein in your meals, especially after your workout, and if you’ve done a resistance or weights session, ideally within 30 minutes of finishing your workout. Focusing on protein in your meals and maintaining an overnight fast is the best way to balance autophagy and mTOR. My favourite way to start the day is with a high protein smoothie or porridge, containing around 30 – 40gms of protein.
4. Resistance training
Research shows that resistance training, in particular, increases muscle size and strength by activating mTOR(g). According to Alan Aragon in Flexible Dieting, “mTOR is a key signalling molecule that regulates muscle growth.” The best of both worlds (the mTOR and autophagy worlds!) is to exercise fasted, and then break that fast with a protein loaded meal. Here’s my favourite recipe.
Final thoughts
We are still learning about mTOR and autophagy and how both processes, when imbalanced, contribute to health and disease. However, you don’t need to wait for science to implement some of these strategies to get the benefits of intermittent fasting, resistance training and protein intake. They hold the key to building a solid foundation for health and being that 80-year-old you want to be.
Before you go…
If you enjoyed this article, share it with friends and family, so they can enjoy it too! And as always, get in touch with me directly if you have any questions or comments.
References:
(b) Schoenfeld, B. J., & Aragon, A. A. (2018). How much protein can the body use in a single meal for muscle-building? Implications for daily protein distribution. Journal of the International Society of Sports Nutrition, 15, 10. https://doi.org/10.1186/s12970-018-0215-1
(c) Song Z, Moore DR, Hodson N, Ward C, Dent JR, O’Leary MF, Shaw AM, Hamilton DL, Sarkar S, Gangloff YG, Hornberger TA, Spriet LL, Heigenhauser GJ, Philp A. Resistance exercise initiates mechanistic target of rapamycin (mTOR) translocation and protein complex co-localisation in human skeletal muscle. Sci Rep. 2017 Jul 10;7(1):5028. doi: 10.1038/s41598–017–05483-x. PMID: 28694500; PMCID: PMC5504043.
(d) Weichhart T. mTOR as Regulator of Lifespan, Aging, and Cellular Senescence: A Mini-Review. Gerontology. 2018;64(2):127–134. doi: 10.1159/000484629. Epub 2017 Dec 1. PMID: 29190625; PMCID: PMC6089343.
(e) Marafie SK, Al-Mulla F, Abubaker J. mTOR: Its Critical Role in Metabolic Diseases, Cancer, and the Aging Process. International Journal of Molecular Sciences. 2024; 25(11):6141. https://doi.org/10.3390/ijms25116141
(g) Joy, J.M., Gundermann, D.M., Lowery, R.P. et al. Phosphatidic acid enhances mTOR signaling and resistance exercise induced hypertrophy. Nutr Metab (Lond) 11, 29 (2014). https://doi.org/10.1186/1743-7075-11-29
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