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How to adjust carbohydrate intake
How to adjust carbohydrate intake is the third article in this short series dedicated to this important source of fuel for physical activity. We have described what are carbohydrates and the use of carbohydrate for sports. In theory, carbohydrate requirements can be calculated knowing a few variables, however in practice there is often a mismatch between estimated and actual requirements. Sources of mismatch Wrong calculations Biological factors These include insulin sensitivity and glucose oxidation rates, which will determine how much carbohydrate the athlete can actually use for fuel. Health conditions Actual vs predicted output In many cases, this is the biggest source of mismatch. Some athletes can predict with a…
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Carbohydrate for sports
The use of carbohydrate for sports has been well-known for several decades. The amount and timing of carbohydrate intake depends on many factors, including the duration, intensity and type of exercise. Roles of carbohydrate in sport As seen in the previous article, the main role of carbohydrate in the body is the production of energy. During exercise, this can translate to: In the time between training or competition bouts, carbohydrate intake is important to: The amount of carbohydrate an athlete requires during and around exercise depends on several factors: It is important to mention the fact that the individual factors listed above can change with habits. When it comes to…
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Training the gut
Training the gut is a sports nutrition strategy designed to allow athletes to handle increased amounts of food and fluid to meet their training and competition requirements. Gastrointestinal symptoms Many athletes, particularly those participating in intense and/or prolonged exercise, suffer from gastrointestinal (GI) discomfort. The symptoms are highly individual and can include bloating, abdominal cramping, diarrhea and vomiting (1, 2). On the most severe end of the spectrum, athletes may experience ischemic colitis and small bowel infarctions, which may require surgical resection (2). Regardless of severity, GI symptoms can certainly affect both performance and recovery (2). Factors The following factors play a role in the development of gastrointestinal symptoms in…
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Nutrient timing
Nutrient timing guidelines are based on the observation that certain nutrients taken at particular times surrounding exercise can improve athletic performance and training adaptations. Nutrient intake is not only necessary for use as fuel during exercise but also necessary for recovery, tissue repair, muscle growth, bone remodelling, immune function, good mood, etc. Generally speaking, you can divide 3 stages: pre, during and post. However, for many athletes there is a blurring of stages as the post-exercise period from one session becomes the pre-exercise period of the next session. Nutrient intake is essential in the pre and post stages, and in some cases during sessions. But it’s not enough with eating…
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Canned and frozen fruits and vegetables
With current social distancing and quarantine measures, many people are relying in canned and frozen fruits and vegetables for their daily nutrient intake. While these foods tend to be regarded as nutritionally inferior, this is not always the case. Canned fruits and vegetables Canned fruits Common canned fruits include apples, pears, peaches, pineapple and fruit salad. Canned fruit (preferably with no added sugar) is considered a suitable substitute for fresh fruit according to the Australian Dietary guidelines (1). However, it is important to note that canned fruit is either packed in fruit juice or syrup. The best option when eating canned fruit is to buy it in juice and drain…
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What is glycogen?
Glycogen is how our bodies store carbohydrate. It is predominantly stored in our muscles and liver and provides the glucose needed for exercise, particularly the high intensity type. What is glycogen? Glycogen is a branched polymer of glucose used as fuel storage. Plants store glucose in starch, we do it in glycogen (1). Most glycogen in the body is located in the muscle (~300-700g) and liver (~100-200g) (2, 3). Each gram of glycogen is stored in our muscles with 3-5g of water. Therefore, carbohydrate loading will lead to weight gain (3, 4). Roles of glycogen Some of the roles of glycogen include: Fuel source, providing carbohydrate to working muscles (2,…
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What are macronutrients?
Macronutrients or “macros” are the components of food that contribute to energy. Energy, in the nutritional sense, is measured in kilocalories (a.k.a. Calories) or kilojoules. The main macronutrients are protein, fat and carbohydrates (a.k.a. “carbs” or “CHO” for the chemistry-minded people out there). Most foods you can think of are made of a combination or these 3 components. Protein Proteins are structures composed of amino acids. There are 7 essential amino acids for humans, meaning our bodies cannot make them. Foods high in protein include: all animal foods (meat, fish, poultry, eggs, milk, etc.), some legumes (beans, chickpeas, lentils, soy), and some nuts and seeds. Protein bioavailability (i.e. how much…
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Eating for training and competition
Nobody would think about running 10km as preparation for an Olympic weightlifting meet. You should be polishing off your lifts and throwing in some max days to simulate competition day. This should translate seamlessly to nutrition. However, many athletes overlook their nutrition strategy and show up to competition with no plan. Eating for training and competition require the same amount of thought. If you are planning to participate in any kind of sporting event, from amateur to elite-level competitions, you should have a nutrition strategy in place. This includes non-competitive events such as martial arts gradings. As you will see below, your nutrition strategy is unique to you because it…
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Self-experiment: 7 day carb test
Guinea pig time! This n=1 experiment comes from Wired to Eat, Robb Wolf latest (and greatest IMO) piece of work. Robb Wolf is one of the most respected voices in the paleo/ancestral scene not only because he was one of the early adopters, but because he gets science, both at an academic level (he is a biochemist) and at a philosophic level (he is not afraid of changing his views when new evidence is available, which is the case with this book). I encourage you to listen to a few of the many podcasts Robb has been interviewed in, so that you get an idea of what his book’s message…
