Everything you need to know about carbohydrates.
As mentioned in my first article about nutrition "You are what you eat" - you should know now that carbohydrates are one of the macronutrients that your body needs to function correctly. (The other two are fats and protein). Let's have a closer look on the carbohydrates to understand why the body needs them.
Carbohydrates (sometimes referred to as “carbs” in the following article) are the primary source of energy for the body. Unfortunately, they are often misunderstood in the context of nutrition. There are so many diets out there that recommend cutting down on carbohydrates which leads us to think that carbs are our enemy. But is that true? What is behind that fear for carbs?
I'm aiming to clarify this topic to assist you in making informed decisions in the future. Keep in mind that everyone is unique and depending on individual goals—whether it's losing weight, gaining weight, increasing energy for sports, or managing medical conditions—recommendations will vary and need to be personalized. It's advisable to consult a nutritionist to discuss your specific needs. In this blog post, I'll provide a general overview of the topic.
What Are Carbohydrates?
Let’s start with clarifying what carbs are. Carbohydrates are organic compounds made up of carbon, hydrogen, and oxygen.
Carbohydrates are found in a variety of foods, including bread, pasta, cereals, fruits, vegetables, grains, and dairy products.
The main function for carbohydrates is to be the primary source of energy, and is crucial for moderate to intense exercise. Carbohydrates provide about 4 kcal/g. You will find carbohydrates in the body mostly as glucose (mainly in the blood) and in form of glycogen storage (mostly in the skeletal muscles and liver)
Classification of carbohydrates:
Carbohydrates can be classified as follows:
1. Sugars (sugars – mono-or disaccharides): Simple carbohydrates, such as glucose, fructose, and sucrose, which are quickly absorbed by the body and provide rapid energy. Sugar just provides energy, but does not contain any vitamins, minerals, nutrients nor fiber.
Monosaccharides (Fructose/Glucose/Galactose)
Disaccharides (Sucrose/Lactose/Maltose)
2. Starches (polysaccharide): Complex carbohydrates found in food like potatoes, rice, and bread. They are composed of long chains of glucose molecules and take longer to digest. Starchy foods contain vitamins and mineral and other nutrients.
Polysaccharide (Starch/Fiber/Glycogen)
3. Cellulose/Fibers (polysaccharide): A type of carbohydrate that the body cannot digest (humans don’t have the enzymes to digest this). It is found in fruits, vegetables, whole grains, and legumes and aids in digestion and maintaining blood sugar levels. Food that provides fibers contains also vitamins, minerals and nutrients.
Polysaccharide (Starch/Fiber/Glycogen)
(saccharide= sugar – mono= one - di=two - poly=many)
General classification of carbohydrates:
The classifications mentioned above can be complex, but there's a simpler way to categorize carbohydrates that everyone can understand and can help making the right food choices- minimally processed carbohydrates and highly processed carbohydrates.
We all know that food is often processed from its natural state to a refined version or packaged form that makes it convenient for quick meal, or snack to satisfy our cravings. Unfortunately, with more processing, nutrients are removed from the food and other ingredients, such as sugars and fats, are added, which just increases the calorie content.
Coming back to the categorization of “good and bad carbs” which is widely used on the internet – this is the correlation to the minimally processed/ highly processed food = >
Good carbohydrates = minimally processed/ nutrient dense carbohydrates
Bad carbohydrates= highly processed – no nutrient/ empty carbohydrates
Here is a short overview on good and bad carbohydrates:
Good Carbs – minimally processed – (nutrient dense carbohydrate food)
Good carbs, also known as complex carbohydrates, provide sustained energy and are rich in nutrients. They are minimally processed and typically high in fiber. They have a low glycemic index (GI), meaning they cause a gradual rise in blood sugar levels. Some examples of good carbs include:
1. Whole Grains: Foods like quinoa, brown rice, oats, and whole wheat products contain the entire grain kernel, including the bran, germ, and endosperm, which provide fiber, vitamins, and minerals.
2. Fruits and Vegetables: These are natural sources of carbohydrates that also offer essential vitamins, minerals, antioxidants, and fiber.
3. Legumes: Beans, lentils, and chickpeas are rich in protein, fiber, and essential nutrients.
4. Nuts and Seeds: These contain healthy fats, protein, and fiber, contributing to sustained energy and satiety.
Bad Carbs – highly processed (so called empty calorie food)
Bad carbs, often referred to as simple carbohydrates or refined carbs, provide quick energy but lack essential nutrients. They typically have a high glycemic index, leading to rapid spikes in blood sugar levels. Consuming excessive amounts of bad carbs can contribute to weight gain, and other health issues. Examples of bad carbs include:
1. Sugary Foods: Candies, cakes, cookies, and sugary beverages are high in added sugars and offer little to no nutritional value.
2. Refined Grains: White bread, white rice, and pastries are processed to remove the bran and germ, stripping away fiber and nutrients
3. Processed Snacks: Chips, crackers, and other packaged snacks often contain refined flours and added sugars.
Minimally processed or unprocessed carbohydrates offer more benefits and provide more sustained energy than highly processed carbohydrates. However, both types of carbohydrates will supply the body with energy. Personally, I am not opposed to athletes using “bad carbs” for immediate energy needs, but only when the situation calls for it. (i.e. during a competition and immediate energy is needed)
In the long term though, consuming only "bad carbs" can lead to malnutrition, various health issues, and obesity.
Here are some tips to make healthier choices
Incorporating more good carbs into your diet can provide numerous health benefits. Here are some tips for making healthier carbohydrate choices:
1. Choose Whole Grains: Opt for whole-grain versions of bread, pasta, and rice instead of refined options.
2. Eat More Vegetables: Aim to fill half your plate with a variety of colorful vegetables at each meal.
3. Include Legumes: Add beans, lentils, and chickpeas to salads, main dishes, and soups for a fiber and protein boost.
4. Limit Sugary Foods and Beverages: Reduce your intake of sweets, sugary drinks, and processed snacks. Choose unsweetened yoghurt and add fruits instead of yoghurt with added sugar.
Always check the nutrition facts labels for added sugars - you will be surprised how much added sugar is in certain drinks, white bread, cereals, sauces like ketchup, BBQ sauce etc.
5. Fruits: Even that fruits are not processed, fruits contain fructose which is known to cause multiple health consequences, such as inflammation, insulin resistance, obesity, and liver disorders. I would recommend limiting eating fruits. (everything in moderation is fine and you don’t have to worry)
To fully understand carbohydrates and their benefits especially for athletes, it’s important to know how the body digests, absorbs and metabolizes carbohydrates.
Here's a simple explanation of how your body processes them:
1. Ingestion: It all starts with ingesting your food that are containing carbohydrates (like bread, pasta, fruits, and vegetables), they enter your digestive system.
2. Digestion: In your mouth, saliva starts breaking down some carbohydrates into simpler sugars. This process continues in your stomach and intestines, where enzymes break down complex carbohydrates (starches and polysaccharides) into simple sugars (monosaccharides like glucose).
3. Absorption: The simple sugars are absorbed into your bloodstream through the walls of your small intestine.
4. Transport: The bloodstream carries glucose to your cells (the hormone "insulin" helps the glucose to get into the cell), where it can be used for energy.
5. Energy Production: Inside your cells, glucose undergoes a process called glycolysis, which breaks it down to produce ATP (adenosine triphosphate), the main energy currency of the cell.
6. Storage: Excess glucose can be converted into glycogen and stored in the liver and muscles for later use. If there is still excess glucose, it can be converted into fat and stored in adipose tissue.
7. Utilization: When your body needs energy, it can quickly convert glycogen back into glucose or break down fat stores to supply energy.
This entire process ensures that your body has a steady supply of energy to perform various functions.
How many carbs are recommended for athletes?
For athletes carbohydrates are the primary source of energy and nutrients. Training and competition reduce carbohydrate storages, and these must be replenished daily. To prevent the depletion of muscle glycogen stores during exercise, athletes should consume a specific percentage of their calories from carbohydrates. This percentage varies depending on factors such as the type of sport, training intensity, and individual metabolism.
For athletes and highly active individuals, the recommended carbohydrate intake ranges from 3 to 12 grams per kilogram of body weight (g/kg). This amount should be tailored to the intensity and duration of the individual's training regimen.
Timing of the carbohydrate intake is also very important – especially immediately after exercise when the muscle glycogen resynthesis occurs.
Normal muscle glycogen is depleted within about 90 minutes of continuous exercise (at 75% VO2 max - VO2 max — or your oxygen uptake — shows how much oxygen your body absorbs and uses while working out. V is for volume, O2 is for oxygen and max is for maximum.)
To extend this time, athletes sometimes use a technique of carbohydrate loading – this is most effective for activities that last longer than 2 hours. (this technique would not make any difference for activities less than 1hour)
But carbohydrate intake is also important before a competition and during a competition. Before a competition research showed that carbohydrate intake 3-4 hours before could be beneficial. (while muscle glycogen storages have been replenished with carbohydrate intake over the last 24-36 hours) Low blood glucose levels are associated with fatigue, so it is crucial to maintain a carbohydrate intake also during exercise as well.
A good and quick solution for carbohydrate intake are sport drinks. Drinks containing too many carbohydrates could lead to gastric distress, so it's important to find a drink that has a good ratio (5-6% of the weight - i.e. 20oz drink that has about 25-30g carbohydrates. The type of carbohydrates should be glucose and sucrose - fructose is not recommended since it does not result in glycogen synthesis rates like with drinks/food that contains glucose and sucrose).
As always, it's important to point out that every athlete is different and everyone has to find a source that is tolerable during exercise to not distress the gastric system.
Here is a good overview of recommendation for the type a activity for daily intake of carbohydrates:
Type of Activity | Recommendation |
Low intensity exercise, technical sports, or skill based activities (golf, etc.) | 3-5 g/kg |
Moderate to high intensity non-endurance activity, some moderate intensity endurance exercise, 1 hour a day | 5-7 g/kg |
High intensity endurance exercise, 1-3 hours a day | 6-10 g/kg |
Extreme commitment, 4-5 hours a day of moderate to high intensity endurance exercise | 8-12 g/kg |
Just as an example- A woman who weighs 145 pounds and who does approximately 8 hours of endurance and non-endurance exercise each week needs about 400 grams of carbohydrates per day. You can find more information on how to calculate this at:
Here is a general guideline on the percentage of carbs an athlete needs per day:
Endurance Athletes: Athletes engaged in endurance sports (e.g., long-distance running, cycling, swimming) typically require a higher percentage of calories from carbohydrates to fuel their aerobic activity and maintain glycogen stores. This can range from 55% to 65% or even higher of total daily calories.
Strength and Power Athletes: Athletes involved in strength training or power sports (e.g., weightlifting, sprinting) generally require slightly less carbohydrates compared to endurance athletes. Their carbohydrate intake may range from 45% to 55% of total daily calories.
Team Sports: Athletes participating in team sports (e.g., soccer, basketball) often have varied energy demands based on the nature of their training and competition schedule. Carbohydrate intake for these athletes may fall within the range of 50% to 60% of total daily calories.
These ranges are general recommendations and can be adjusted based on individual needs, preferences, and specific training goals. It's essential for athletes to work with sports nutritionists or dietitians to fine-tune their carbohydrate intake to optimize performance and recovery.
I hope this article helped you understand that the role of carbohydrates in our diet is crucial for maintaining good health and optimizing performance, especially for athletes. Carbohydrates, whether minimally processed or highly processed, provide essential energy for the body. However, minimally processed carbohydrates, often referred to as "good carbs," offer additional nutritional benefits and sustained energy, while highly processed "bad carbs" can give fast energy, but typically have a high glycemic index, leading to rapid spikes in blood sugar levels, and lead to health issues if consumed excessively and long term.
For athletes, proper carbohydrate intake and its timing is essential for fueling performance and recovery. The specific needs vary based on the type of sport, training intensity, and individual metabolism. Consulting a nutritionist or dietitian can help tailor carbohydrate intake to meet personal goals and optimize health and performance.
Next time I will let you know all about PROTEIN!
Till then - stay happy and healthy
Christiana
FUN FACT:
DID YOU KNOW: Carbohydrates are a necessary source of fuel for the brain?
Brain cells need twice as much energy as other cells in the body. When carbohydrates break down, they create glucose, which is the brain’s preferred and primary energy source and helps it to function properly. It’s estimated that the brain needs 110-145 grams of glucose per day.
Resources:
Marie Dunford, J. Andrew Doyle - Nutrition for Sports and Exercise, Fourth Edition, Cengage, 2017
Jenkins, D. J., Wolever, T. M., Taylor, R. H., Barker, H., Fielden, H., Baldwin, J. M.,& Goff, D. V. (1981). Glycemic index of foods: a physiological basis for carbohydrate exchange. The American Journal of Clinical Nutrition, 34(3), 362-366.Slavin, J. L. (2005). Dietary fiber and body weight. Nutrition, 21(3), 411-418.Ludwig, D. S. (2002). The glycemic index: physiological mechanisms relating to obesity, diabetes, and cardiovascular disease. JAMA, 287(18), 2414-2423
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