Carbohydrates for Protein Synthesis
For natural lifters, building muscle at optimal speed is difficult if you are not consuming carbohydrates. I'm not saying that you can NOT do this if your protein and calorie intake is high enough, but it gets a lot harder.
How can carbohydrates, consumed during the training period, increase muscle growth? Is not muscle made of protein?
Yes, but carbohydrates and the insulin production they lead to will increase mTOR expression in training. If you consume carbs before or during exercise, the mTOR will be activated more than if you did not. And the more you activate mTOR, the more your protein synthesis is enhanced through training.
This is important for natural lifters who need to initiate protein synthesis with their lifting sessions. Although drug users also benefit from carbohydrate during exercise, they do not need it as much as they already get a huge protein synthesis from the steroids.
Carbohydrates and Cortisol
When carbohydrates are present during exercise, it also has other benefits to positively increase muscle growth.
Carbohydrates before and / or during exercise reduce cortisol release. During the session, the main function of cortisol is to mobilize nutrients for exercise. When lifting, glucose is the most efficient source of fuel. (Yes, even more than ketones.) The more fuel you need to mobilize, the higher the cortisol production.
If you provide slightly absorbed carbohydrates such as highly branched cyclic dextrin before and during exercise, you will have less to mobilize stored glycogen, which means you will not have to pump off as much cortisol. Less cortisol means more growth.
Carbs in training can also increase capacity to have a higher training volume (more readily available fuel, reduced cortisol content) and grow from it.
Carbohydrates and IGF-1
Low-carb diets lead to lower levels of systemic IGF-1. This is well documented in many studies. This is probably due to the fact that both growth hormone and insulin are required to produce a large amount of IGF-1.
They do not necessarily exist at the same time. One theory suggests that insulin makes the liver more sensitive to the production of IGF-1 when growth hormone is released. Why is that important? Because IGF-1 is the most anabolic hormone in the body.
You do not need a lot of carbs all day, but enough to stimulate insulin secretion once or twice a day will certainly help build muscle
How many carbohydrates? For more information, see the first related link.
The Best Damn Diet for Natural Lifters
Low Carb Diets and Cortisol