Carbohydrate supplements during training: more is better?

Carbohydrates are our bodies fuel during physical activity. Let’s see together what quantities are needed during training.

It is well established that carbohydrates are considered the best selected fuel for guaranteeing a good performance during all types of sports. The practice of replenishing or maintaining glycogen stores during physical activity is very common (endogenous sugar reservoir to be used during exercise in order to maintain the right glycemic levels in the blood).

At this point it’s important to ask two questions:

• What types of carbohydrates?
• How much?

Types of carbohydrates

To answer the question connected to what types of carbohydrates should be taken, the answers can be multiple according to when the person needs them to be assimilated into the system. Times are roughly related to the complexity of the molecules introduced; a chain maltodextrin 20/21 or 23 requires around 20 minutes to be metabolized and become available.

Molecules like fructose are monosaccharides, even more so glucose (we are talking about single chains with different absorption mechanisms) the time needed for them to be assimilated into the system vary from 1/5 to 7/20 minutes, maltodextrins instead, according to their chain length take between 15 to 60 min.

On the market it’s possible to find single carbohydrates or a mixture in order to provide quick energy (usually burned in a short period of time and useful for sprints) or medium/slow energy: this second option ensures a lasting supply that is gradually and slowly released into the body.

The energy needed varies according to the type of performance and according to the intensity and type of exercise.

A solution that contains 0.6 g of maltodextrins for every 0.4 g of fructose for every kg of weight is considered to be the best formula for achieving high carbohydrate oxidation during exercise without having intestinal problems.

This is why an athlete weighing 70 kg may take 70 g of carbohydrates each hour, meaning 30/35 g every 30/40 min, an ideal timing for achieving a constant reintegration (always related to the intensity of the exercise).

By using different mixtures it is possible to “potentially” increase the oxidation up to +50%, but this result is not universal and needs to be compared to the capacity/habits of the individual athlete and also to the time needed for the supplements to be assimilated.
Tests performed on cyclists who have taken 120 g/h of carbohydrates as they worked 75/80% Vo2 Max show that they experienced less benefits in comparison to 70 g because higher carbohydrate quantities causr gastrointestinal problems.

It’s also important to make sure that the concentration of the maltodextrin mixture (or other sugars) respect the right osmolarity (mOsm/kg) to ensure a good transit and gastroenteric absorption.

Usually 5 or maximum 10% formulas are preferred.

To understand better, this means that in a 500 g bottle, it is recommended to dilute up to 25g of maltodextrins or even up to 50 g, only by extending transit times.

OSMOLARITY = Concentration of a solution expressed in the number of active particles for each liter. (the higher is the molecular weight (PM) the better osmolarity within the solution)

Gastric emptying

Type and volume of the drink that passes through the stomach during 20 minutes
Tupe (% glucosio)         Velume in Ml
O (pure water)            64
5                               60
8                               55
10                              47
15                              36
20                              20

The formula intake may be as follows:

HYPERTONIC = The “solutes” concentration (sugars and mineral salts) is higher than blood plasma. Absorption during long periods of time.

ISOTONIC = The “solutes” concentration is similar to blood plasma. Medium-fast absorption.

HYPOTONIC = The “solutes” concentration is lower than blood plasma. Quick absorption times for the liquid and nutrients. Quicker and highly efficient balance restoration achieved by preventing dehydration and the weakening of body functionalities before or during training or competing.

Transition and absorption times are clearly restricted by this parameter.

From these considerations, an athlete may choose to take supplements with high carbohydrate quantities within each individual dose (even 80/100 g); unfortunately, in reality this goes in contrast with the actual capacity of the digestive system to receive and absorb such high quantities.

Some believe gels bypass this problem, but this is absolutely false.

By taking thick gels the person inevitability needs to drink more (to dilute the solution), and this isn’t the only problem; it can easily happen that high quantities of sugar may cause gastric imbalance which in turn prompt absorption problems.

The type of sugars taken need a medium brief release period and at the same time they have to guarantee high absorption without causing hydro or intestinal imbalances.

A note needs to be added in relation to additional gels containing nervine substances like caffeine that ensure a higher effectiveness on the nervous system; gels coupled with amino acid formulas may increase the energy restoration by blocking completely the catabolic effect caused by aerobic activities.

As always, supplement quality and studies made on their formulation go beyond simple active ingredient quantities because times are studied, especially when it comes to maintaining the metabolic balance of complex systems activated during an athlete’s performance.