Earlier, we introduced the concept of intermittent fasting, a dietary pattern that is gaining popularity because of its potential to aid fat loss. By limiting a day’s calories to a 4-to-8-hour span and fasting the rest of the day (for many, this works out to skipping breakfast and dessert), it is possible to influence insulin values and sensitivity within the body, as well as help deplete glucose and glycogen, meaning body fat stores are targeted for energy.
However, research suggests that even muscle-builders stand to benefit from intermittent fasting, and it’s all because fasted states tend to produce more growth hormone — and the studies have shown this for quite a long time.
A Washington University study done in the 1960s asserts what we still know today as a gospel truth: You secrete more growth hormone (GH) while you sleep. Further, the study shows that going to bed in a fasted state — your body really favors burning fat here, especially when there is a shortage of blood sugar or glycogen stored in the muscles — further primes the metabolism for anabolic activity (again, all going back to the pancreas and insulin).
Now, add in resistance training to this mix, and you’re creating a perfect storm of sorts: The fasted state you stay in until right after your training session increases the production of GH. The fasted sleep you got the night before this has done it even more. And the protein-and-carb-heavy meal you consume immediately after training pretty much throws the whole muscle-building, fat-burning process into motion by signaling to the pancreas to release anabolic insulin, which carries glycogen to your muscles for immediate recovery — and, because of your previously fasted state, there isn’t left-over blood sugar waiting to be used or burned, so your body doesn’t need to store it as fat.
A 2003 Sports Medicine study explains the benefits of exercise on growth hormone production:
Resistance training results in a significant EIGR (Exercise-Induced GRowth hormone). Evidence suggests that load and frequency are determining factors in the regulation of hGH (human growth hormone) secretion. Despite the significant EIGR induced by resistance training, much of the stimulus for protein synthesis has been attributed to insulin-like growth factor-1 with modest contributions from the hGH-GH receptor interaction on the cell membrane. (Source)
In short, you’re bolstering your GH production four ways: Sleep, fasting, exercise and timed eating. And the hunger that you might first experience when adopting intermittent fasting subsides, fast — remember, we’re a species that spent centuries not knowing from where or when our next meal was coming from. We were hungry a lot. Our bodies produce a substance called Ghrelin that basically decides when we feel hungry, for how long, and what to do with metabolic energy. And, as you might’ve guessed from our theme here, it plays a role in signaling the release of growth hormone when we do eat. Its name is cutely derived: (Growth Hormone Release-Inducing = Ghrelin)
Once your body knows (yes, your body learns, and very quickly) that you’re not going to be eating every three hours, and that a fasting period is coming, hunger side effects like crankiness and morning irritability from skipping breakfast will fade. Ghrelin will make sure of that.
The bottom line on intermittent fasting, as far as hormones go, is that research strongly indicates it can provide a significantly anabolic, fat-burning environment based on the body’s hormonal responses to the changes it would go through. And who doesn’t want that?