How many carbohydrates do we actually need… Part II
Are carbohydrates essential, and how important are they?
Contrary to what you often hear, our body has no real, direct physiological requirement for carbohydrates. Even several nutrition books acknowledge this before going on to recommend that “a sensible diet should nevertheless still contain a relatively large amount of carbohydrates”.
To understand why carbohydrates aren’t actually essential, we need to understand the importance and non-importance of different nutrients as a whole. In short, a nutrient’s essentiality and irreplaceability are determined by the following:
1. A nutrient is essential if our normal functioning and survival depend on it.
2. It is important to get a nutrient from food if our body is not able to produce it from other nutrients itself.
The second criterion is largely what decides whether carbohydrates are truly vital or not: our body is perfectly capable of producing glucose from other nutrients, and as much as the brain and certain tissues need every day. Of course, our body can’t produce carbohydrates from other nutrients to the extent that would also guarantee stores for high-intensity activities such as sprinting or strength training. Accordingly, for people who do that kind of training, a certain daily amount of carbohydrates can understandably be considered necessary. We’ll come back to that later.
But if we’re talking simply about functioning and survival, the minimum amount of carbohydrates the body should get per day is 0 grams. The small minimum amounts of glucose that certain tissues need each day can be readily produced by our body from other nutrients. If you’re wondering which nutrients, read on.
What can the body make glucose from?
Even if carbohydrates are heavily restricted and there is no direct reason to consume them, the body still has a small need for this nutrient (although even this minimal need decreases over time). In a carbohydrate deficit, the body has to find ways to meet this required minimum and produce glucose. Those ways are lactate, pyruvate (breakdown products of glucose metabolism), glycerol (a breakdown product of fat metabolism) and some amino acids. Using amino acids to make glucose is somewhat problematic, because those amino acids have to come from “somewhere” too. When you’re in a deep deficit and eating little, that “somewhere” generally means muscle tissue (the body also uses liver proteins); so to meet its minimal glucose need, the body starts breaking down proteins to obtain amino acids, which in turn can be used to produce glucose.
Muscle proteins are among the first to be targeted, because the released alanine and glutamine can easily be converted into glucose in the liver. This process is called gluconeogenesis: the process by which glucose is produced from amino acids. In a deep and prolonged energy deficit or in outright starvation, especially in its early stage, the use of protein for energy is particularly high. It gradually decreases as the brain switches over and learns to use ketone bodies for energy. This ability of the body and brain to adapt significantly reduces the demand for direct carbohydrates, which also means sparing protein rather than using it for energy. But even despite this adaptability, heavy calorie restriction or exceeding certain deficit limits always means, of course, that the body’s proteins get broken down and used for energy. And if this goes on for a long period, it proves harmful to our health. Not to mention that you lose muscle mass, and with it strength, performance and the ability to function normally.
The role of the liver and the importance of protein metabolism under diet conditions are very often, regrettably, overlooked. Yet it is a fact that in a deficit, more than half of the amino acids passing through the liver are broken down, and a large share of them is used precisely for glucose synthesis.
Translator’s note: in other words, when the body is in an energy deficit, even a slight shortfall, the amino acids absorbed from the gut into the blood pass through the liver, and under deficit conditions a large share of them starts being converted into glucose to make up for it. That is why protein intake needs to be raised: so that something is left for the muscles too, and so that the protein synthesis “machine” keeps running. The fact is that we can’t do without a deficit either, because it is a necessary condition for body fat to burn at all. How deep a deficit to go into is a question of its own, but who could be the one to say “hold exactly this deficit, then fat will burn and most amino acids will stay for the muscles instead of being oxidized for energy”? Who knows that, and what is that deficit? It simply can’t be said! If I have to choose whether to optimize burning fat for energy (both in terms of the daily total and the speed), but at the price of large and very large daily protein rations, then of course I will do it. What’s more, with large protein rations I have a “letter of guarantee”: if I provide the body with enough protein even under deficit conditions, I will very likely manage to hold on to muscle mass and strength in a deficit too.
This is also the fundamental reason why protein needs always go up during a diet. In a deficit, the liver automatically starts breaking down more amino acids and converting them into glucose. For this reason, and so that an optimal amount of protein is left to support protein synthesis and muscle retention/growth, protein amounts need to be raised.
As long as the amount of protein is high enough, there is no particular physiological need for carbohydrates either; this is also the main message of my book “Rapid Fat Loss”: eliminate all non-essential nutrients and ensure the maximum of all the nutrients that are of primary importance to the body (if the goal is fat burning and we are operating in an energy deficit, these primary essential nutrients are an adequate amount of high-quality protein and beneficial fatty acids). These are the necessary conditions for creating the maximum deficit with the minimum loss of muscle mass at the same time.
Suppose you don’t want to eat large amounts of protein: how many carbohydrates per day would you need to prevent muscle protein loss while dieting?
How many carbohydrates do you need to prevent the mass oxidation of body and muscle protein for energy?
Even quite old studies show that on a low-carbohydrate diet, as little as 15 grams of carbohydrates reduces the body’s nitrogen loss. Raising that amount to 50 grams a day means the body practically doesn’t have to convert amino acids into glucose at all. That is also why, in my book “The Ultimate Diet 2.0”, I recommend a daily carbohydrate intake of 50 grams.
1. 50 grams of carbohydrates a day can keep blood glucose and insulin at an adequate level (this is necessary to prevent the release of cortisol)
2. This amount of carbohydrates can feed the brain nicely while substantially limiting the breakdown of the body’s protein.
Basically, when we talk about dieting, there are two options: either raise your protein intake to make up, in a sense, for the missing carbohydrates, or simply eat somewhat more carbohydrates. Both approaches lead to the same end result. 15 – 50 grams of carbohydrates a day largely reduces the body’s need to convert its own structural protein into glucose. Likewise, compared with 0 grams of carbohydrates, even this amount lets you lower your daily protein intake significantly.
Translator’s note: referring to the author’s sentence “Basically, when we talk about dieting, there are two options: either raise your protein intake to make up, in a sense, for the missing carbohydrates, or simply eat somewhat more carbohydrates”, is this really always a dilemma, and are these always alternatives? Perhaps, to see some result, you do sometimes have to get by on a very small amount of carbohydrates for certain periods? Or are these alternating periods within a diet, and are those the situations we should be manipulating?
To be continued…
Author: Janar Rückenberg (translation)
Source:Turg.Fitness.ee
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