Dr Delanghe, Waterloo Chiropractor



53650544 - foods high in carbohydrate on rustic wooden background. top view

There has been a burst of social media hype around the idea of using very low carbohydrate (ketogenic or keto) diets for endurance events. The keto diet usually consists of 5-10% of total kcal (~50g or less) from carbohydrates per day, 75% from fat and 10-20% from protein, although there is no set standard of carbohydrate level. In this article I want to talk about how the body uses energy during exercise before we get into the research.

If we look at the stores of energy in the body, we know that our ability to store carbohydrates as glycogen is limited. We can store carbohydrates in our muscles and liver and the more trained an individual is the more they can store, however it is still limited and can only supply about 1500-2000kcal and muscle glycogen is depleted within 1hour of intense exercise. Fat on the other hand is very calorically dense and we can store 65 000 kcals (could fuel about 20 marathons!) in our adipose (fat) tissue and within the muscle. Fat can supply significantly more energy than carbohydrates without supplementation. This diet is seen as attractive because it promotes the idea that we can max out our capacity to burn fat as a fuel while running, reducing the amount of food or energy we need to take on the run. Therefore, it seems logical to adopt a keto diet, max out our ability to burn fat as a fuel, right? Well let’s look at this topic a little deeper.

low carb


Understanding Energy Production During Activity

Our body uses two processed to produce energy in the form of adenoside triphosphate (ATP). The first method is anaerobic (without oxygen) and the second is aerobic (with oxygen). There are 3 energy systems that the body uses depending on a few factors, such as intensity, length of event, and availability of oxygen.

(1) Phosphocreatine System

This system is the quickest way to produce energy and is the first system to turn on to crank out ATP. Let’s say as you are reading this article your fire alarm stated to ring, you would immediately jump up and run out the door. In this fight or flight response you are using mostly the phosphocreatine system. It works by taking the phosphocreatine that is stored in the muscles, and through an enzymatic reaction the phosphate is split off and added to adenosine diphosphate to make ATP. This is a very simple reaction, and the body can use this system for about 8-10 seconds before it’s tapped out. This system can recover; it takes about 4 minutes before the system is ready for another intense bout.

(2) Anaerobic glycolysis

This is the second system to turn on to support energy production. To continue with out analogy from above, after our initial jumping and sprinting for the door, after the 8ish seconds our body tends to rely more heavily on the anaerobic glycolysis system. This system uses carbohydrates (glucose) and through a series of steps breaks down 1 glucose molecule into 2 pyruvate molecules. Without oxygen, this pyruvate can be further broken down into lactate and a hydrogen ion and ATP. This system will last about 1-2 minutes. In repeated sprints, such as hockey shifts, research shows that subsequent sprints rely on anaerobic glycolysis to provide 50% of the energy.

(3) Oxidative phosphorylation (Aerobic system)

This system takes a while to get warmed up and to get going once you start exercising. In untrained individuals, it can take a few minutes for this engine to get running fully, but in elite athletes it can fully turn on within about 30-60seconds. In our analogy above, lets say we lived in the country and we needed to go run to the fire station down the road, after our initial sprint and quick getaway, our aerobic system turns on and produces a majority of the energy needed. This system can last forever; at rest we are aerobically oxidizing mostly fats to provide energy for the body at rest.

The aerobic system can burn carbohydrates, fat and protein depending on availability and intensity. Protein used in very small amounts to provide energy for exercise and we wont discuss it further here. I want to discuss the differences between fat and carbohydrate oxidation.

The classic study from Romijn et al. showed that the fuel sources changed depending on the intensity of exercise. They looked at 25% VO2Max, 65% VO2Max and 85% VO2Max. The found that as intensity increased, so did caloric expenditure and the more intense exercise relied more heavily on carbohydrate use. This is because at higher intensity of exercise the fat breakdown and transport into the mitochondria and oxidation rates are too slow to keep up with the energy demands.


Carbohydrate is also the preferred fuel during intense activity as it provides 5.5% more kcal/L of oxygen compared to fat oxidation, meaning it is a more efficient fuel source. Research shows that elite level marathoners fuel use is 85% carbohydrate and 15% fat oxidation.

One thing to note is, you do not only use one system at a time, your aerobic system is always running in the back ground. Think of these systems like dimmer switches, they can be turned up or turned down depending on the situation. For example, if we take a cyclist who is riding on a flat surface, they have their aerobic system pumping out most of the ATP to cover the cost of their cycling. When they hit a hill, there is an increased demand for ATP. The aerobic system take a little while to adjust, and therefore the anaerobic system has to kick in to provide some quick energy, and that means the phosphocreatine system turns on, and the anaerobic glycolytic system turns on to meet the ATP needs of the body.

Key points:

  • Fat is slower to provide energy, and therefore intensity is lower when using fat as a fuel source
  • Fat is less efficient; it uses more oxygen to produce less ATP
  • High burst of exercise- ie the energy change when cycling or running up a hill is usually covered by anaerobic glycolysis which uses glucose (carbohydrate)
  • Most elite athletes run at high %VO2 and burn a large amount of carbohydrates


Romijn JA, Coyle EF, Sidossis LS, Gastaldelli A, Horowitz JF, Endert E, Wolfe RR. Regulation of endogenous fat and carbohydrate metabolism in relation to exercise intensity and duration. Am J Physiol. 1993;265:E380-E391.

O’Brien MJ, Viguie CA, Mazzeo RS, et al. Carbohydrate dependence during marathon running. Med Sci Sports Exerc. 1993;25:1009–1017. doi: 10.1249/00005768-199309000-00007

Bosch, AN, Goslin BR, Noakes TD, Dennis SC. Physiological differences between black and white runners during a treadmill marathon. Eur J Appl Physiol. 1990;61:68-72.


Vit D

By: Stephanie Boville MSc., RD

As the snow and cold weather rolls in, it is often accompanied by the common cold or worse, the flu. Endurance athletes are more at risk of illness, specifically upper respiratory tract infections (URTI) because they often engage in intense training sessions outdoors that often last over an hour and athletes who are overtrained are even more at risk. Studies show that runners training for 96km/week doubled their odds of illness compared to those training only 32km/week and about 40% of marathoners experience an URTI in the 2 months of winter training leading up to a marathon race.

Along with the vigorous training, other factors such as stress, lack of sleep and inadequate nutrition can lead to immune suppression, increasing risk of illness. Being a Registered Dietitian, I would like to explain how vitamin D may help boost your immune function this winter season.

Immune function in athletes:

There are a few reasons why URTI’s are common, although this is not a complete list of all the immunological changes that occur with heavy exercise, it will provide background as to why illness is specific to the upper respiratory system.

  1. Cortisol, a stress hormone, is increased which temporarily suppress the immune system.
  2. Specific biomarkers of inflammation increase and have been linked to immune suppression.
  3. Natural Killer cell (cells that kill viruses) activity is reduced for at least 6 hours by 40-60% following exercise lasting over an hour.
  4. Nasal neutrophil phagocytosis (cells responsible for searching for and destroying bacteria) is decreased
  5. Nasal and salivary Immunoglobuin A (IgA) (antibodies secreted in the saliva which are responsible for protecting the immunity of the respiratory tract) concentration is decreased by 70% for 18h after a 31km race.
  6. Nasal mucociliary transit time is prolonged post marathon race for several days, meaning the movement of foreign particles and bacteria out of the upper respiratory tract and away from the lungs is less efficient.

All of these aspects combined demonstrate that there is possibly a window of increased risk of contracting an URTI after exercise because the immune system is compromised. The last three points demonstrate a few possible reasons to why the upper respiratory tract is so vulnerable, especially because the nose and throat are the first line of defense against pathogens entering the body.

Nutrition and Immunity:

The first point I want to make is that overall adequate nutrition plays a role in maintaining a healthy immune system. If we look at the IOC paper discussing the consequences athletes face when they are in a relative energy deficient state (inadequate overall energy intake), we see that one of the many systems affected is immunity. Therefore, you might want to think again before you try and “shred those Christmas and New Year’s gains” in mid flu season unless absolutely necessary. We need to understand that good dietary basics are necessary to support a healthy immune system before we start to get more specific with our micronutrients.

Vitamin D and Immunity:

There are three studies I want to discuss:

Study 1:

Study 1 was an observational study investigating the effects of vitamin D status on the incidence and immune function during winter training in 239 endurance athletes. They found that being vitamin D deficient resulted in significantly more symptom days and increased symptom severity of URTI when compared to optimal, adequate and inadequate vitamin D levels. They also investigated saliva samples which showed that salivary IgA concentration was significantly reduced in athletes with deficient levels of vitamin D, and that athletes with adequate, inadequate and deficient levels of vitamin D had reduced salivary IgA secretion rates compared to optimal levels. From the information in the paragraphs about we see that one area in common, the salivary IgA. Both exercise and reduced levels of vitamin D results in decreased salivary IgA concentration and secretion rates which suggests that having an optimal levels of vitamin D has an important role to play in maintaining immunity in athletes. Lastly this study found that the antimicrobial peptides in the blood were positively correlated with vitamin D status suggesting that optimal vitamin D may result in better immune function and protection.

One limitations of this study is that it was an observational study and therefore no clear links can be determined whether an intervention with vitamin D supplement in vitamin D deficient athletes will reduce frequency, length and severity of illness. Rather this study concludes that there is an association between reduced vitamin D status and increased illness length and severity along with reductions in immunological markers.

Study 2:

Study 2 investigated the effect of a 2000IU vitamin D supplement on length and severity of URTI in non-athletic adults. They supplemented participants for 12 weeks with Vitamin D or placebo and found no differences in URTI incident or severity. However, there are a few things to consider. First, we know athletes have a higher risk of URTI’s, and therefore the results may not be generalizable to an athletic population. Second, even though there was a significant increase in Vitamin D levels with supplementation it was not enough to get participants to an “optimal” level as set out by study 1 and vitamin D levels may not have been sufficient enough to show changes in immunity. Third, both groups had adequate baseline levels of vitamin D and it could be possible immune function is only compromised at inadequate or deficient levels of vitamin D. Fourth they did not do any salivary or plasma samples and therefore we can not see the immunological changes.

Study 3:

Study 3 investigated the effects of 14 weeks of 5000IU vitamin D3 supplements in 39 athletes on antimicrobial peptides and proteins. They found that the 5000IU dose for 14 weeks was enough to elevate blood levels of vitamin D to optimal levels and that 14 weeks of winter training without supplementation decreased vitamin D levels. 5000 IU of vitamin D per day resulted in significantly higher percent change in antimicrobial peptide concentration compared to placebo and increased the salivary IgA and antimicrobial peptide secretion rates. Therefore, their conclusion was that optimal vitamin D may help up-regulate the systems needed to protect against URTI.

Some limitations of this study include participants started at adequate levels of vitamin D and therefore the changes might underestimate the importance of vitamin D’s effect on immunity and bigger changes might be seen when vitamin D levels start at an inadequate/deficient level. Another limitation to this study is they did not record incidents of URTI and therefore no conclusion could be made as to whether the immunological changes resulted in decreased illness.

Main points:

Research has clearly demonstrated that vitamin D is of critical importance in the bodies immune system however there is more to learn about how vitamin D levels impact the frequency of illness and severity, and at what level is the immune system compromised.

From the studies above we learn that:

  1. Optimal levels of vitamin D increase antibacterial peptides in the blood
  2. Optimal levels increase salivary IgA secretion rates and concentration
  3. Observational studies show that illness severity and length is decreased compared to lower levels of vitamin D.

Because salivary IgA is suppressed after intense exercise and taking vitamin D increases the IgA secretion rate and concentration, this may be one mechanism that optimal vitamin D is used in to protect against upper respiratory tract infections.

Practical application:

Should we be supplementing? Usually my belief is “food first, supplement second”. With that being said, there are few foods that contain high levels of vitamin D. We can make vitamin D from the sun, however we are too far north for adequate sun exposure to make vitamin D this time of year (fall through spring). Even in the summer we may make inadequate amounts of vitamin D from the sun if we wear sunscreen, have dark skin or train inside or early/later in the evening. It is likely a good idea to supplement to make sure you are getting adequate amounts of vitamin D. Not only does it play a role in immunity, but it also helps maintain bone and muscle health, and therefore it is an important nutrient.

How much vitamin D: Health Canada has set the Adequate Intake (AI) level of vitamin D at 600 International Units (IU)/day and the upper limit at 4000 IU/day for most ages with some exceptions. First AI means that there is not sufficient evidence to set a Recommended Dietary Allowance (set to meet the needs of 97-98% of healthy individuals) but the AI is assumed to be adequate. There is debate about the AI for vitamin D as many think this AI is set too low, and people are also supplementing over the upper limit (like in study 3 from above). In the following years this AI could see and increase.

Food Sources: People often think milk is the best source of vitamin D, however 1 cup of milk only provides around 100IU or 1/6 of your daily needs of vitamin D. One of the best sources is actually salmon, which, depending on the kind can provide anywhere between 200-600IU in one 2.5oz serving (the size of a deck of cards).

Supplements: Depending on diet and your current vitamin D status, supplementing with 1000-2000IU is should be enough to give your vitamin D levels a boost and is recommended, especially in the winter.

There are many other tactics athletes can try to maintain and help with increased immune function. If you would like to learn more, book an appointment so we can optimize your nutrition intake to support your health, wellbeing and athletic performance!

Related Article: Does Vitamin C help to prevent the common cold?  Check out Dr. Delanghe’s past article.


Nieman, D.C. Exercise effects on systemic immunity. Immunology and Cell Biology. 2000. 78: 496-501.

Gleeson, M. Immunological aspects of sport nutrition. Immunology and Cell Biology. 2016. 94: 117-123.

He, C.S., Handzlik, M., Fraser, W.D., Muhamad, A., Preston, H., Richardson, A., Gleeson, M. Influence of vitamin D status on respiratory infection incidence and immune function during 4 months of winter training in endurance sport athletes. Exerc Immunol Rev. 2013. 19: 86–101.

Li-Ng M., Aloia, J.F., Pollack, S., Cunha B.A., Mikhail, M., Yeh, J., & Berbari N. A randomized controlled trial of Vitamin D3 Supplementation for the prevention of symptomatic upper respiratory tract infections. Epidemiol. Infect. 2009. 137: 1396-1404.

He, C.S., Fraser, W.D., Tang, J., Brown, K., Renwich, S., Rudland-Thomas, J., Teah, J., Tanqueray E., & Gleeson. M. The effects of 14 weeks of vitamin D3 supplementation on antimicrobial peptides and proteins in athletes. Journal of Sports Sciences. 2016. 34: 67-74.

Version 3

We are extremely excited to welcome the newest member of the Delanghe Chiropractic and Health team: Stephanie Boville MSc, RD.

From weight loss and managing osteoarthritis, all the way to sports nutrition, Stephanie will be here to help you conquer any and all of your dietary concerns and goals!  With 6 years of post secondary education, and a strong science/evidence- based approach, only advice based on the BEST available research will be implemented.

No cleanses, magic powders or fad diets and no guessing.

How many grams of carbohydrates will you need to optimize your marathon performance?  Are you getting in enough protein to maintain muscle and enhance performance?  Are you taking in the right foods to decrease the pain and inflammation associated with arthritis?  Stephanie can help you!

What it takes to be an RD:

The process of becoming a registered dietitian is unlike any other designation for those offering advice on diet.  RDs are highly educated and trusted professionals for a reason!

The first step in becoming a dietitian is to complete a 4 year undergraduate degree from an accredited university program.  Once the future dietitian has completed their undergraduate degree, they must apply to an accredited internship program or masters program, which can be very competitive and must be accepted within 3 years of graduating from their undergraduate degree. The internship or masters program require the future dietitian to complete various competencies and log hours working under a certified dietitians. Rotations include public or community health settings, food service, diabetes, inpatient units and outpatient units within the hospital. If that isn’t enough, the dietitian is then required to write a 6 hour regulatory exam to demonstrate their knowledge and competence of being employed as a dietitian before they receive certification. Once the dietitian receives their certification, they are required to submit yearly self directed learning tools to prove to the college that they are committed to continuing their education and improving their skills in their nutrition practice. They are also subjected to randomly being selected for peer and practice assessment where the dietitian is evaluated by both patients and co-workers to assess their work performance and competency. If anything unusual is revealed in these assessments there could be further investigation by the college into the dietitian and action if they are found to be incompetent.  Because of this long road to become a RD, it’s clear why they can be the professionals trusted with your dietary health!

To learn more about Stephanie and her hours, click HERE.

Too book an appointment, call (519)885-4930.

Book your appointment

Contact us to book your next appointment

Call Us 519 885 4930