The Low Carb Diet: What Does it Consist of?

11th April 2020
Restricting their carb intake may not be a valid option for some people, particularly when we consider athletes who practice certain training disciplines.

When it comes to losing weight, there’s a multitude of protocols and diets that we can put into practice. One that has gained considerable strength in recent years is the low carb diet. What does it consist of? Is it effective?

It’s a type of diet that many consider as being ‘restrictive’, as it limits the intake of one of the main macronutrients. But, it offers the advantage of a rapid weight loss.

This loss happens because, in the absence of carbs, our body uses fats as the main energy source, which stimulates weight loss. Let’s analyze how much about this is true and how to follow a low carb diet the right way.

Physiological mechanisms of the low carb diet

The human body uses glucose as the main energy molecule. We can obtain glucose in two ways: by consuming foods rich in carbohydrates or by endogenous mechanisms or glucose production from fatty acids and amino acids.

The low carb diet takes advantage of this second metabolic pathway, which happens in the liver. When plasma glucose levels drop, and we empty our glycogen reservoirs, a process that’s known as gluconeogenesis (GNG) begins.

Through this route, the body obtains glucose to use as energy from amino acids and fatty acids. First, it uses the ones circulating in the plasma. But when those levels drop, the body burns fatty and muscular tissue to get the energy that it needs.

However, the body prioritizes the destruction of fatty tissue over muscle tissue, unless we’re suffering from malnutrition or fasting for a prolonged period.

Does this diet work?

We can find studies comparing the low carb diet to a low-fat diet. Weight loss results are usually similar. However, there are people who prefer to restrict carbs in their diets, as they claim this way they don’t have as much appetite.

Carbs provide energy for intense workouts

The physiological mechanisms of hunger are closely related to the effectiveness of these diets. Appetite is regulated in part by a hormonal mechanism. Ghrelin is the hormone that stimulates hunger and it depends on the glucose levels circulating in the blood, and therefore, it depends on insulin as well.

An athlete looking at her food options to obatain the energy she needs

When we consume carbs, especially in high amounts or in variations with a high glycemic index, we experience a blood sugar spike. After this peak, what follows is reactive hypoglycemia or postprandial hypoglycemia, which lowers blood sugar levels and stimulates appetite, despite having eaten a short time ago.

Therefore, low-fat diets are more likely to cause a feeling of hunger. To alleviate this effect, we can usually use fiber.

However, in the low carb diet, the glucose curve remains stable. On the other hand, fat intake can induce a feeling of satiety since it delays gastric emptying. In these situations, the individual usually reports less feeling of hunger.

It’s not a diet suitable for everyone

The low carb diet has certain restrictions regarding its use. First of all, people who are diabetic must be very careful, as they have certain particularities in the management of their glucose curve.

On the other hand, not everyone is able to follow this type of diet as closely as they should. In the first days of carb suppression, they can experience symptoms of a “withdrawal syndrome”. On top of that, this may cause vomiting, nausea or diarrhea, which causes many patients to abandon the diet in the first week.

However, once they complete the adaptation process, it’s easier to stick to the diet. As we previously discussed, it also allows the individual to experience less appetite than with a low-fat diet, even in low-calorie conditions.

Athletes are another group of people that should be careful when following a low carb diet. For endurance athletes, there are usually not many complications, since as with most of the exercises, the glucose they use comes from the transformation of fatty acids. However, when talking about strength athletes, this may not be the case.

Fiber is also an important element

The most important deficiency that this type of diet presents in terms of health is probably a low contribution of fiber. Scientific literature positively correlates fiber intake with the prevention of some types of gastrointestinal cancer. Therefore, low intakes of this substance can be harmful to our health in the medium and long term.

Woman eating a bowl of cereal rich in fiber to compensate for the lack of this substance in the low carb diet

In this type of situation, it’s convenient to increase the intake of vegetables other than fruit; this is because they contain high amounts of sugar. Furthermore, supplementing with pro and prebiotics may be an interesting way to guarantee the biodiversity of our microbiota.

Low carb diet: conclusion

The low carb diet can be effective for weight loss, thanks to its effects on satiety. However, a specialist must supervise it; since it’s a restrictive diet, it can easily cause deficiencies.

Lastly, another option is to lower our carb intake a little, instead of restricting them completely. In short, everything depends on the situation and goals of each person, as well as the evaluation made by the nutrition professional in each particular case.

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