Fueling your body for better training

16 March 2021

By Laura Martinelli, Team Novo Nordisk Nutritionist

Blood sugar drops due to enhanced insulin sensitivity and accelerated glucose consumption during exercise. Athletes know the term carbo-loading very well but research shows a greater dietary balance between the main macronutrients might be more beneficial. 

The key word to address this is “periodization”: an early concept in sports nutrition science, in which I firmly believe.

If in the past, athletes used to manipulate only the carbohydrate and the caloric intake of their diets, nowadays the whole bromatological composition of the diet is taken into consideration. Moreover, also the timing distribution of those components throughout the day is becoming more and more important.

Therefore, according to the specific period (and consequent target) of the sports year, we can modulate not only carbohydrates, but also protein, fat, fibers, antioxidants… to reach our specific aim: from improving performance, to enhancing recovery, to maximizing training stimulus or optimizing sleep quality, for example.

With the same tools (basically, nutrients and timings), we “play” and we periodize nutrition, in accordance with training and competition needs. 

What does it mean to burn fat instead of sugar and how should we behave at a dietary level to support this type of low-intensity activity?

The body tends to prioritize the fuel ingested before the workout. Therefore, if my breakfast before training is built on carbohydrates, then my body will strive for oxidizing carbohydrates as main source of energy during training.

The fueling during the training itself submits to the same physiological rules: the greater the carbohydrate intake, the higher the contribution of the carbs as energy source during the effort; and vice versa.

Consequently, to maximize the fat burning potential and efficiency is essential to diminish the carbohydrate sources before and during training, preferring a protein-based breakfast and combining some protein sources (i.e. protein bottles or protein bars) alongside the more traditional carbohydrates ones.

But please note that this nutrition strategy is not aiming to maximize performance, but to increase the muscle fat utilization during low-intensity activity; for races this is definitely not an option.

Can you talk about a ketogenic diet? Proteins are a big talking point today. Can they become the main fuel for athletes?

If the athlete wants to lose fat and work on his fat burning efficiency, I’d say yes, without doubt. If the athlete is thinking to perform at his best following a ketogenic diet, I fully disagree.

The impact of a ketogenic diet on athletic performance has sparked much interest during the last decades, nonetheless there is now a literature overwhelming consensus that a ketogenic diet increases the risk of impaired performance with the likelihood of an unavoidable depletion of carbohydrate stores: in other words, to maximize your performance the fueling has to be built on carbohydrates.

Nevertheless, there may be a few scenarios where ketogenic diets are of benefit, or at least not detrimental for sports performance; but road cycling is not one of them.

Photo by Dan Gold on Unsplash

Carbohydrates can be of two types, complex and simple. When and how should they be taken?

In sports nutrition the distinction has to be even more meticulous, as carbohydrates are not only divided into complex and simple, but also in “fast release” and “slow release” ones. In other words, we need to evaluate their impact on blood glucose levels to decide when and how we should place them in the athlete’s daily nutrition habits.

In particular, slow-release carbohydrates (i.e. wholegrain pasta, basmati rice, oatmeal, rye bread, honey, agave syrup…) represent the ideal glucidic base of the pre-training meal because they assure a consistent energy levels till the first part of the exercise, avoiding the risk of a rebound hypoglycemia potentially caused by fast-release carbohydrates (i.e. breakfast cereals, rice milk, biscuits, white bread, sugars, ripe fruits, standard pasta, potatoes…).

On the contrary, those latter are excellent ingredients for the post-training meal, to boost and maximize the glycogen store replenishment.

How do you prevent hypoglycemia (low blood sugar) during exercise? 

The best way to prevent hypoglycemia during exercise is to plan the nutrition strategy in advance, test it in training and then being able to adapt it according to the unpredictable variables of the race.

That said, theoretically the athlete should base their nutrition strategy on slow release carbohydrates (i.e. energy bars and isotonic drink) and then regularly add some fast-release ones, such as gels and shots. This blend of different carbohydrates blunts the initial glycemic peak and keep blood glucose stable throughout the workout, avoiding reactive hypoglycemia and consequent performance impairment.

Ending with your question: in training, the quantity might range from 40 to 80 grams of carbohydrate per hour, in the race from 60 to 100 grams per hour.

The size of the snack (if the training is between main meals) depends on the duration and intensity of your workout. The harder and longer your muscles are working, the more carbohydrates you will need in order to maintain your blood sugar level. Does that sound right?

Yes, definitely. The pre-training meal has always to be made up of carbohydrates (pasta, rice and oatmeal are the most appreciated among riders) and the quantity adjusted according to the intensity and the duration of the session: the longer and the harder the training, the bigger the plate of pasta!

Moreover, if the training is particularly demanding and/or the weather conditions extreme, then a good tip is to add some sources of lean protein (i.e. bresaola, chicken breast, white fish, omelets…); meanwhile always minimizing the ingestion of fat (i.e. nuts or sauces) and fibers (i.e. vegetables and legumes), which might slow down the digestive process.

Finally, what should the “perfect” post activity meal be?

A beer if it’s a one-stage race!

Joking… even if it’s always important to consider the specific target of that day. if my primary aim is to focus on recovery and get ready for the training of the day after, it would be great that my post-activity were a full plate of white rice with some bresaola, and afterwards a medium portion of fruit salad as recently it has been reported from the literature in the area that combining glucose (from the rice) and fructose (from the fruits) is likely to speed up the recovery process, so why not?

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