The physiology of fasting is fascinating. The power of fasting lies not in the mere reduction of calories, but the beneficial hormonal changes. One of the main benefits comes from reducing insulin, but there are also increases in nor-adrenalin, cortisol, and growth hormone. Collectively, these are known as the counter-regulatory hormones, since they all serve to increase blood glucose at a time that the body is not getting glucose from food. Here we focus on human growth hormone (HGH).
HGH is a hormone made by the pituitary gland (the master gland), which plays a huge role in the normal development of children and adolescents as the name implies. However, it also plays a role in adults. HGH deficiency in adults leads to higher levels of body fat, lower lean body mass (sarcopenia) and decreased bone mass (osteopenia). Growth hormone is typically secreted during sleep and is one of the so-called counter-regulatory hormones. HGH along with cortisol and adrenalin increases blood glucose by breaking down glycogen – so it counters the effect of insulin, hence its name. These hormones are typically secreted in a pulse just before waking (4 am or so) during the ‘counter-regulatory surge’. This is normal and is meant to get the body ready for the upcoming day by pushing some glucose out of storage and into the blood where it is available for energy.
When people say that you ‘must’ eat breakfast to have energy for the day, they are completely wrong. Your body has already given you a big shot of the good stuff and fueled you up for the day ahead. This is also the reason why hunger is lowest first thing in the morning (8 am) even though you have not eaten for 12 hours or so.
Fasting is a great stimulus to HGH secretion. During fasting, there is the spike in the early morning, but there is regular secretion throughout the day as well. This HGH is crucial in the maintenance of lean mass – both muscle and bone.
Training in the fasted state. Increased nor-adrenalin from fasting will pump you up to train harder. At the same time, the elevated HGH stimulated by fasting should increase muscle mass and make recovery from a workout easier and faster.
Benefits:
- Insulin levels: Blood levels of insulin drop significantly, which facilitates fat burning (1).
- Human growth hormone: The blood levels of growth hormone may increase as much as 5-fold (2, 3). Higher levels of this hormone facilitate fat burning and muscle gain, and have numerous other benefits (4, 5).
- Cellular repair: The body induces important cellular repair processes, such as removing waste material from cells (6).
- Gene expression: There are beneficial changes in several genes and molecules related to longevity and protection against disease
- Intermittent fasting helps you eat fewer calories, while boosting metabolism slightly. It is a very effective tool to lose weight and belly fat.
- Intermittent fasting can reduce insulin resistance and lower blood sugar levels, at least in men.
- Studies show that intermittent fasting can reduce oxidative damage and inflammation in the body. This should have benefits against aging and development of numerous diseases.
- Intermittent fasting may have important benefits for brain health. It may increase growth of new neurons and protect the brain from damage.
- Studies in animals suggest that intermittent fasting may be protective against neurodegenerative diseases like Alzheimer’s disease.
Research shows that counting calories and limiting your food options make dieting a chore and causes stress which often leads to abandonment of the diet, feelings of deprivation, uncontrolled cravings, and weight regain. Adapting to intermittent fasting, a method of scheduled eating and fasting, relies strictly on time. Some people want more flexibility when it comes to losing weight. Rather than saying ‘just eat less’ we tell them not to eat after 6 p.m. and for those who have the discipline, it works.
The biggest beneficial effects of fasting come from 3 things:
- Autophagy – the cell’s self-digestive mechanism that recycles waste material and old proteins into energy. This greatly improves your health and life-span.
- Ketosis – the metabolic state with elevated level of ketone bodies in the bloodstream. This makes you burn primarily fat for fuel from your own adipose tissue. Ketones are a much better source of energy for the brain because they cause less oxidative stress and they last for longer.
- Hormesis – the body’s adaptive mechanism to mild stress. This will trigger protective metabolic pathways such as AMPK that increase mitochondrial density and boost the immune system. Hermetic stressors in the right dose will make the organism stronger than it was before.
Therapeutic benefits of intermittent fasting
- Protects your brain: intermittent fasting encourages and speeds up the production of the brain-derived neurotrophic factor, which makes neurons more resistant to dysfunction and degeneration. Ultimately, this kind of eating plan will help your brain stay in tip-top shape, and slow down its degeneration.
- Intermittent Fasting slows ageing: this way of life mimics caloric restriction, which is the most effective way we know of to increase lifespan. When you fast, it gives your cells some time to detox and recycle, so your body can slow down the ageing process and even help prevent age-related diseases.
- Increases in the Human Growth Hormone (HGH): during intermittent fasting, HGH has shown to increase as much as five times over. This hormone is produced by the pituitary gland, and increases glucose levels, and is therefore suppressed during feeding. Fasting is a great stimulus for secretion of HGH. This particular hormone is important for athletes due to its anabolic effect and its ability to help muscles recover quickly.
- Induces cellular repair (also called auto phagocytosis): During a period of fasting, the body induces processes that are vital to cellular repair. Fasting helps the removal of waste material from cells. A study done by Cell Stem Cell shows that fasting actually shifts stem cells from a dormant state to a state of self-generation. These cells are also regenerated in the immune system.
- Reduces inflammation: inflammation in the body is the leading cause of so many illnesses. Fasting helps reduce oxidative stress, along with preventing and fighting inflammation in the body.
- Facilitating weight loss: intermittent fasting has been proven to aid weight loss in individuals. This is because of the change in hormone levels which facilitates weight loss. In addition to lower insulin and increased HGH, intermittent fasting increases the release of the fat burning hormone norepinephrine. Additionally, studies have shown that short-term fasting may increase the metabolic rate by 3.6-14%. These same studies have shown that people lost 4-7% of their waist circumference, resulting in a reduction of harmful belly fat that builds up around the organs and causes diseases.
References:
https://www.dietdoctor.com/intermittent-fasting
https://www.muscleforlife.com/the-definitive-guide-to-intermittent-fasting/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6128599/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4516560/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6836017/
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