Myth or reality Maltodextrin (“Malto”) the 3 days before a race ? As a sports dietician, I can answer you in total transparency.
Why a diet specific to sportmen (with or without maltodextrin) ?
Who doesn’t know the mythical “marathon wall” (the impression of being armophous and without juice !) And that many have encountered at least once in their life (and which can be mitigated by taking a commercial sports drink or homemade sports drink). On the physiological level, this corresponds, among other things, to a significant decrease in muscular glycogen stocks (energy reserve for sugar). In the 1960s, researchers in sports dietetics tried to find solutions to start compétitions with optimal reserves of glycogen (hepatic but especially muscular). The purpose is that the more our stocks are important at the start, the more the possible arrival of the wall moves away !
Different food concepts have been tested. The first studies were carbohydrate overload in untrained athlètes during the seven days preceding an endurance test. Then the evolution was, the dissociated dietetics arrived in two times, bearing the name of ” Scandinavian dissociated diet”. The first phase (generally three to four days) consisted of a low carbohydrate diet combined with intense exercise to minimize glycogne stores followed by a second phase (three to four days) rich in carbohydrates associated or not with less intense exercises.
In recent times, this diet has been modified a little : it essentially includes an increase in carbohydrate dietary intake during the last three days before the competition, more pratical to set up in the field. Glycogenic overcompensation is shown to be optimal for a high carbohydrate diet (10-12g/ kg/ day) over three days before the test.
Next comes the question : which type(s) of carbohydrate prefer ? Some authors believe that carbohydrates with a high glycemic index (GI) should be preferred, others with low GI carbohydrates, and some believe that the type of carbohydrate isn’t the most important.
Maltodextrin : who are you ?
Still called Malto by some bitumen buffs but not that, it’s more necessary to see this appointment as a set of molécules, identical and different at the same time. Then in the singular or in the plural ?
Maltodextrins are a group of carbohydrate entities (“sugars”) resulting from the more or less partial hydrolysis of starch (hydrolysis = “some form of digestion”), usually wheat or maize, tapioca starch or potato. This last molecule, starch, is a complex carbohydrate, called polysaccharide (“several sugars”), composed of chains of glucose molécules (or detrose, a basic element called “sugar” directly assimilable by the organism) to a reserve molecule for higher plants and to an essential component of the human diet.
Indeed, this carbohydrate allows an energy supply to the body to ensure not only its vital functions (heart, brain …) but also and especially its muscular functions solicited importantly during the practice of sport. This is one of the limiting factors in endurance sports such as marathons, ultra, ironman triathlon, raids of all kinds but also for explosive sports such as bodybuilding, martial arts, racquet sports ….
Dextrose equivalent : the key term of maltodextrin or how to differentiate them ?
When we speak of maltodextrin, we refer to a mixture of several “sugars” resulting from the hydrolysis of starch, comprising a number of different carbohydrate entities (oligosaccharides, maltrotriose, maltose, glucose, ect .). An index is given for the degree of hydrolysis. Thus, DE is referred to as Dextrose Equivalent. The higher it’s, the higher the hydrolysis and the shorter the chains, the more tends towards a number of glucose molécules per weak chains. This is the principle of “digestion” !
On a scale of values from 0 to 100 :
- DE= 0 : corresponds to unconverted starch
- DE= 100 : corresponds to pure glucose (or dextrose), or totally transformed (hydrolyzed) starch ;
- 0< DE <20 : corresponds to the state of maltodextrins ;
- DE>20 : corresponds to glucose syrup (name found on the list of ingrédients of the products coming from the Agr-Food Industry or AFI).
Between an ED of 0 and 20 (for maltodextrins), there are therefore a multitude of combinations of maltodextrin ! Thus, the lower the DE, the lower the Glycemic Index (GI) will be, and vice versa ! It’s for this reason that we speak of several maltodextrins and not of a single form.
Interests of maltodextrin
There are several uses in the athlete at three distinct times : before, during and after the effort. Maltodextrin is used as a nutritional supplement, the sole objective of wich is to enrich the carbohydrate diet so that it can be easily used by the body.
They’re well tolerated by the body, there’re feww negative returns concerning possible digestive disorders, its digestion is very correct, except if the consumption is excessive (much like any type of food). Their taste remains rather neutral (interesting for sports where the effort is prolonged over time with an important drink in quantity and over time!), little sweet (especially since the DE is low), they are ordorless and easily dissolved, very interesting for powder formulations to dilute with water !
The proportion of maltodextrin is fairly high in terms of waiting (before), effort (recovery) and recovery (after).
Remark : Another interesting point of the maltodextrins is an osmolarity (to explain simply, “quantity of molécules per volume of liquid”) lower bringing a same quota of energy compared to exclusive drinks in glucose and/or fructose. This is very convenient for obtaining hypotonic or isotonic sports diet drinks adapted to the physiology around and during exercise (in particular gastric emptying and assimilation).
“Slow sugar” or “Fast sugar” ?
Firstly, the terms “slow or fast sugars” are no longer up to date, although often used by athletes for simplicity ! Indeed, let us take the example of white bread, it has a high glycemic index (GI) but is considered as slow sugar (and there are many examples). It’s now neceesary to use the notion of Glycemic index (GI), which represents the impact of food on blood glucose (blood sugar level). A carbohydrate with a low GI (a case of fructose) causes a low glycemic response (low glycemic elevation), a carbohydrate with a high GI causes an important response to blood glucose (the case of glucose or sucrose, white sugar, for example).
I advise you, for information, my article dealing with the Glycemic Index.
There isn’t only one maltodextrin ! Because of their more or less complete “amylaceous hydrolyzate” characteristics, there are as many glycemic indexes as there are different maltodextrin ! They’re called “liquid pastes” in the sporting environment, they have a character of carbohydrates with low, high or intermediate glycemic index depending on their ED. Overall, their GI is often higher than low with an ED of between 15 and 20. The “liquid noodle” loses its credibility, because very often the athletes use this type of supplement to ensure intake as starchy, important, in non-solid form (thus more flexible than to swallow 1kg of straches), ans a few days before the competition.
Thus, on the partical side and to summarize, a dietary drink integrating exclusively maltodextrins having low EDs possesses a low GI (without glucose, dextrose for example but with fructose optionally in composition), which is advantageous for waiting periods and setting in reserve of glycogen the few days before the competition (principle of the overcompensation linked to the dissociated regime for example well known to the sportsmen).
Conversely, a dietary drink with maltodextrins with a high DE (greater than 15), with glucose, dextrose, but without fructose in the composition, has a high GI with the known effects on blood glucose in period out of effort!
The concrete case of the drink of a famous French sports dietetic brand
Many sportsmen use this kind of drink the 3 days before a sporting event. When I say this kind, I’m talking about a drink made up only of maltodextrins in terms (but potentially associated with some vitamins or minerals).
The terms chosen by this brand (leading in France on this type of product) to describe their dietetic product based on maltrodextrins are as follows : “The consumption of Malto, made up of 96% of slow carbohydrates, is a considerable asset because it Ensures the growth of your glycogenic reserves without having to eat a lot : you eat reasonable amounts at meals and your hydration is ideal in perpective of the test”. (See screenshot).
I have deliberately emphasized the term “slow carbohydrates” because, as I have demonstrated above, only the DE of maltodextrins is oriented more towards a low or intermediate, or even high GI.
The DE of their maltodextrin included in this drink is found to be 18 (indicated by a ditetician working for that brand), indicating that it has a GI that is more favorable to intermediate, even high than low and is therefore not optimal to have a “slow carbohydrate” as could fructose (which has a low GI), if consumed alone of course. Then there is the complexity of the food ration that comes to interact with this product based on maltodextrins and which generally reduces its basic GI (interactions with the fibers, proteins, fats, texture of food …)
So here is the conclusion of this point, the marketing around maltodextrins is Paramount and many sportsmen who believe to use a product for an effect that it has not concretely!
Note : This relevant sport dietetic brand was the first to respond and to be transparent in relation to the composition of their maltodextrin product, which is not the case for certain brands contacted. One even goes so far as to say that they aren’t allowed to give ED because it is an industrial measure of the classification of sugars : it’s therefore a “secret” to know what I can potentially consume!
Conclusion on maltodetrin
For athletes in search of performance, I recommend that athletes reduce their training during the last days before the competition and significantly increase their carbohydrate intake (9 to 12g/ kg/ day) the 3 days before departure : See my Régime Dissocié Modifié (Modified Dissociated Plan). On the practical side, I advise most of the time that this increase is done in part with the intake of a drink of glucose-based effort. How to increase carbohydrate intake? It’s difficult for the diet alone to reach the desired level of carbohydrates. I also recommend using carbohydrate intake effort drinks (“maltodextrins + glucose + fructose” or “maltodextrins + fructose”) and / or stress bars based on glucose and / or fructose, to significantly increase its carbohydrate ration.
Finally, the maltodextrins are composed of 1 to 9% glucose and have for the most part high glycemic indexes (ie “fast assimilation”). Concretely, is it necessary to consume maltodextrin-type drinks to increase its carbohydrate intake in order to overcompensate in glycogen ? I do not think so since there’s no evidence to date of the efficacy of maltodextrins alone to increase glycogenic reserves. Thus, beverages containing only higher-than-low GI maltodextrins have no significant superior interest compared to a substantially glucose and / or especially fructose beverage, to achieve “glycogenic storage”, if not the commercial side. Indeed, they are often advocated by sports marketing to increase our reserves of glycogen.
Sports Dietitian Nutritionist