1. Where does our body get energy from?When we think about providing energy to our body, we automatically imagine the "burning" of glucose (carbohydrates) and fats as a substrate and food for each of our cells to do their job. Glucose, obtained mainly from carbohydrate sources such as bread, legumes, cereals, fruits and vegetables, is one of the main sources of energy for animals and humans.
2. The role of glucose in our bodySome of the carbohydrates we eat are used to maintain blood glucose levels . Likewise, they participate in the fact that it is used as fuel in certain organs, those that are not capable of using fat as an energy source. In this way, the unused glucose is either deposited in the liver and muscles, in the form of glycogen , or is converted into adipose tissue, that is, body fat . When we stop incorporating external sources of glucose through the diet, we can "release" stored glycogen, and convert it back to glucose, with the aim of maintaining stable blood sugar levels. This is what happens, for example, when we fast. However, we must exercise caution. In the case of not having enough stored glycogen , and in the absence of a glucose supply through food, the body can enter into the process called neoglucogenesis , where glucose will be obtained from non-carbohydrate precursors. If prolonged over time, this transformation can cause a negative effect on the nervous system or skeletal muscle.
3. When should I use fat and when glucose?Understanding how your body works not only enables you to manage and adapt your eating habits, but also opens the doors to raising your state of physical and mental health to a higher level. For example, during ketosis, an optimal environment is generated to fight a bacterium, while in the early phases of a viral infection we need glucose to fight it. If we look at the sports field, nutritional ketosis is ideal for covering long distances and, on the other hand, glycolysis will be vital to face the sprint to the finish line. On the other hand, there is evidence on the benefits of ketogenic protocols in certain phases of the menstrual cycle, attenuating the body's inflammatory response. However, it will not be the most appropriate protocol in the same phase of the cycle if you want to get pregnant . As in everything, there are nuances, since a person can be in ketosis while their body is perfectly capable of resorting to glycogen stores when the context requires it. This is why the key lies in metabolic flexibility , that is, in teaching our body to easily alter the use of fat and glucose .
4. Importance of Metabolic FlexibilityBroadly speaking, a person with metabolic flexibility is able to immediately change fuel , or energy substrate, according to their availability and need. Therefore, people with good metabolic flexibility will have better performance and a greater facility to burn body fat . Conventional diets and the current lifestyle, dominated by " I don't even have time to breathe", are largely responsible for the low metabolic flexibility of the population . Something that is directly related to the increase in cases of diabetes and obesity . Being “glucodependent”, or a slave to glucose , generates hormonal imbalances in the body that we can identify as follows:
4.1. glucose spikesGlucose ingested through carbohydrate-rich foods is not rapidly transported into the cell. In this way, it remains in the blood and generates very high glucose peaks . A person with metabolic flexibility easily secretes insulin, allowing glucose to enter the cell and the remainder to be transported to the liver to be stored as glycogen. We may resort to these reserves when our personal context so requires.
4.2. absence of glucoseIn the absence of glucose , for example after twelve hours of fasting, the body tries to obtain glucose as an energy source, being forced to break down muscle tissue (catabolism) to continue producing this fuel (gluconeogenesis). This is because you do not have the ability to easily enter ketosis, a state in which the breakdown of muscle tissue is prevented and energy is extracted from adipose tissue, that is, from fat.
4.3. Physical activityDuring physical activity , the body directly uses stored glycogen, regardless of the degree of sports intensity, and therefore fatigue appears much earlier. In contrast, when you have metabolic flexibility , the body will only resort to glycogen when it has to face great efforts and, in general, it will use fat as fuel .
4.4. Little metabolic flexibilityPeople with little or no metabolic flexibility live with a constant demand for glucose, cravings and the need to eat sweets at all hours to "reactivate" their energy levels. In addition, they hardly last half a day without eating. From all this, we know that flexibility is the key to stability . If you want to learn how to add versatility to achieve metabolic flexibility, don't miss this practical proposal that we have prepared for you .
- Estradiol and the control of feeding behavior . Science Direct, 2017.11.11
- FGF21 contributes to neuroendocrine control of female reproduction . NCBI 2013.09
- Metabolic flexibility and obesity in children and youth . NCBI 2010.10.26
- The sedentary (r)evolution: Have we lost our metabolic flexibility? . NCBI 2018.02.02