mTOR stands for “mechanistic target of rapamycin,” a group of enzymes in the body that regulates the function of proteins, including protein synthesis. In fact, it’s the primary regulator for muscle cell protein synthesis and inhibitor of protein breakdown. The more proteins that the body synthesizes, the more it leads to muscular hypertrophy. Therefore, if your goal is muscle growth, knowing a bit more about mTOR is important.
The body stimulates mTOR to get moving through several methods:
- mTOR is triggered when muscles are put under mechanical stress, such as weight lifting (specifically eccentric training), and when stretching the muscle under load.
- The release of insulin also activates the mTOR pathway. That’s why post post-workout nutrition is so essential. When you properly fuel your body after a hard workout, insulin production is increased in response to elevated blood glucose levels. Post-workout carbs will trigger a sufficient insulin response to activate the mTOR pathway, which, in turn, will promote protein synthesis.
- Branched chain amino acids (BCAAs). Three BCAAs—valine, leucine and isoleucine—are considered essential amino acids because the body cannot manufacture them on its own and they must be consumed through foods and/or supplements. These essential amino acids are especially important for weight lifters, as an adequate supply of BCAA’s preserves muscle glycogen stores, which is the prime fuel source that keeps muscles working and reduces muscle fatigue.
But BCAAs also have the capacity to activate mTOR, especially leucine, which has been shown to be especially effective in protein synthesis.
To elicit mTOR, you need to train and fuel your body properly appropriately:
Eccentric Training/Muscle Stretching
To stimulate muscle growth through mTOR activation, start by eccentrically lowering the weight slowly for a count of five seconds, making sure to keep the target muscle tensed/flexed while lowering. When the muscle is fully lengthened, hold in a stretched position for a count of two. For the last rep, hold the stretch for as long as comfortably possible.
An effective post-workout fueling includes 30-40 grams of carbohydrates, as this amount will trigger the insulin response to boost mTOR activation. Good choices include
- Whole-grain cereals and breads
- Sweet potatoes
- Brown rice
- Chickpeas or other legumes
BCAAs and Leucine
All three BCAAs mentioned earlier are present in whey protein powder, which could make it an ideal option for post-workout nutrition to trigger muscle growth. However, you can also consume BCAAs through whole foods, such as eggs and egg whites, chicken and turkey breast, beef, salmon and canned tuna. For those who are vegetarian or vegan, roasted peanuts are surprisingly high in all three BCAAs.
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