Fasting vs low-carb diets

Fasting vs low-carb diets

Understanding the difference

Fasting can be understood as the voluntary stop of any kind of food consumption for a certain period of time. Low carb diets can be understood as the consumption mostly of foods that contain low percentage of carbohydrates and that present mostly fats and/or proteins.

Both approaches have been getting attention in the last decades as ways of counteracting the growing obesity and diabetes problems. The reason for this being that both approaches reduce partially (in the case of low carb) or completely (in the case of fasting) the ingestion of foods composed mostly of carbohydrates in an attempt to break the insulin increase cycle.

In this article we will compare both in terms of how they affect insulin levels (we won’t touch other levels).

And how if your objective is to lose weight fasting could be a better option, and how these two options relate to insulin levels. To understand why insulin levels are important we have to understand what is insulin and its role on our metabolism.

What is insulin

Insulin is the hormone in charge of inducing the acquisition of glucose from the media into the cells. This means that the presence of insulin is what makes it so that cells can incorporate glucose as a source of energy.

But insulin doesn’t only have a role in this, it is also involved in the process of turning the excess glucose, that which we can’t use as energy or turn into glycogen, into fat.

This means that insulin is pivotal in controlling the production of fat from what we eat, but not only that, but it also participates in the fat metabolism by inhibiting processes that induce ”fat burning” as a source of energy.

This translates into the fact that if our insulin levels are too high we cant acess all our  fats as a source of energy and not only that, but we will be more prone to increasing this fats storage.

The pyramid’s lie


Once that we know why insulin is important we can understand the difference between these 2 approaches. To start we have to understand one simple fact, and that is that ” levels of insulin always spike after a meal”. The reason for this is the interaction between our body and the different macronutrients in our food.

The different macronutrients in a meal are carbohydrates, proteins and fats, and the response of insulin to each of them is different. In order of how strong is the increase of insulin levels for each of them we can see that carbohydrates are the ones that induce the highest increase in insulin levels, followed by proteins and fats.

What this means is that eating the food that usually forms part of the ”normal” diet will produce a high increase in insulin levels, due to the fact that many of us have been taught that the correct diet is one where we eat carbohydrate reach foods such as bread. And this in turn will reduce the quantity of fat burned since insulin induces fat storage and it would be counterproductive to burn what you are trying to store, we could think of insulin as an artisan and of fats as their work, no artisan would burn the work they poured their energy into, unless they had no other choice.

How do they affect insulin

If we take into account what we just explained  you may think, ”Hey why don’t we just go with a low carb diet?”.

You could be right if your objective mainly to reduce weight this could be a pretty reasonable approach since you would cut on the macronutrient that produces the highest effect in insulin levels, but the problem is that it isn’t the only one.

Metaphor of how low carb still produces a slight spike in insulin
Photo by Derek Thomson on Unsplash

As we explained before proteins also induce a spike in insulin levels, albeit a smaller increase that carbohydrate rich foods, and this would mean that if your insulin resistance is high it may not be enough to reduce the levels of insulin and lose weight. Although low carb diets are a pretty good option to maintain your current weight in a pretty healthy way.

Now that we know how insulin responds to different macronutrient levels we can understand why fasting and low carb diets are different.

The answer is that since you don’t ingest any kind of food while fasting, your insulin levels will be bound to drop with time since your only energy source are the fats you have stored and only by decreasing the insulin levels can you fully access this energy. Meaning that fasting could be a pretty interesting way to reduce the insulin levels and fat stored, and this second fact could help you lose weight.

Metaphor of howfasting doesn’t produce spikes in insulin
Photo by Luke Stackpoole on Unsplash

For more articles about health and nutrition follow the link. If you liked this post and want more subscribe to our newsletter.

Although as I just said fasting could be interesting as an approach I don’t recommend following any of the conclusions we reach in the articles without consulting with a professional since this decisions affect your health and you should always check with your physician.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.