Day 9. Carbohydrates


The Science Behind Carbohydrates and Weight Loss 

With all of the dietary trends in today’s world of health and wellness, it is not uncommon for carbohydrates to be viewed in a negative light. Similarly, dietary fat was also once seen as a macronutrient to severely limit or avoid because “it could make you fat.” With ever expanding research into how food affects the human body, we now know that dietary fat is beneficial in a variety of cases.1 The same is true with carbohydrates.

Regardless of how fancy the name of a new diet craze is, carbohydrates serve an important role in normal human functioning. No one macronutrient is more important than another. We need all of them for optimum metabolic health.

The Science Behind Carbs

Carbohydrates primarily serve as the most readily usable source of energy for our bodies. When digested, carbohydrates turn into blood glucose, which provides energy for our cells. Furthermore, chains of glucose provide usable energy for physical activity in the form of muscle glycogen.2 This energy is crucial for your workouts.

A lack of energy, particularly a feeling of lethargy or mental fogginess, is often the result of low blood sugar levels. While low energy levels can happen to anyone on occasion, a more serious condition is called hypoglycemia.This is a dangerously low level of blood glucose in the body that can be harmful if left untreated.

And since how we treat our bodies at the cellular level impacts our metabolic health, severely limiting or avoiding carbohydrates altogether will likely not produce positive health outcomes. Thus, we advocate having a balance of healthy carbohydrates as well as other key macronutrients in the form of healthy fat and protein consumption.

1. Estruch, R., Martínez-González, M., Corella, D., & Salas-Salvadó (2016). Effect of a high-fat Mediter- ranean diet on bodyweight and waist circumference: a prespecified secondary outcomes analysis of the PREDIMED randomized controlled trial. The Lancet Diabetes & Endocrinology, 4(8), pp.666-676.
2. Berg, J., Tymoczko, J. and Stryer, L. (2017). Glycogen Metabolism. [online] Available at: [Accessed 17 Jul. 2017].
3. American Diabetes Association. (2017). Hypoglycemia (Low Blood Glucose). [online] Available at: mia-low-blood.html [Accessed 17 Jul. 2017].

Why Carbs Matter

To understand where healthy carbohydrates come from, it is important to first understand that there are different types of carbs, each of which digest differently. As they each differ in rates
of digestion, they also differ in their effect on blood sugar. The three main sources of carbs are starch, sugar, and fiber.4


These can be considered complex carbohydrates because they digest at a slower rate. Slower digestion is good for normal blood sugar regulation. Starchy vegetables include peas, lima beans, and even sweet potatoes.
Grains also fall under this category. Broadly, they can be broken down into two categories: whole grain and refined (or processed) grain.

Whole grains contain three layers: the bran, germ, and endosperm. These layers make the body work harder to digest, so it slows the digestion rate. This, again, is a good thing for normal blood sugar regulation.

Refined or processed grains lack these layers which make them digest quickly. You want to avoid fast digestion because it leads to spiked blood sugar levels. If the body has consistently high blood sugar levels, a condition called insulin resistance can develop, which is a hallmark sign of Type II Diabetes. Additionally, because the body can’t use all of the glucose, the excess energy gets stored as fat, leading to weight gain.

It is important to remember that while slow digestion is preferable, this does not mean you can consume as many servings of complex carbohydrates as you desire. Frequently having more than the serving size recommends can still lead to excess blood sugar levels and weight gain. Carefully follow the GetFit21 Food Guide when it comes to choosing appropriate sources of starchy carbohydrates, and remember to follow recommended serving sizes. By sticking to recommended serving sizes, you give your body the energy it needs to sustain normal blood sugar levels. The foods to enjoy section will empower you to choose the right sources and avoid the processed ones.


You’ll find this type of carbohydrate in foods like fruit and table sugar. Fruit contains fructose, and regular table sugar contains sucrose. You’ll find sucrose in most sweetened goods, such as cookies and cake.

If you’re following the GetFit21 Food Guide, fruit is the only healthy way to include carbohydrates from sugar in your diet. Remember to keep serving size in mind, even when eating fruit. All other sugars should be avoided unless it is your reset meal, as they can cause blood sugar spikes without providing any nutritional content.


This comes from plant sources and is indigestible. It helps with digestive health, aiding in bowel movement regularity. Furthermore, fiber also helps with satiety, keeping you fuller after a meal because of how it slows the digestion process.

4. American Diabetes Association. (2017). Types of Carbohydrates. [online] Available at: http://www. html [Accessed 17 Jul. 2017].

Make it Happen

Understanding how to balance healthy sources of carbohydrates for optimum metabolic health is empowering! You now know that it matters where carbs are coming from and how they digest. You also know that normal blood sugar levels are ideal for metabolic health. So what do you do with this knowledge? In short, follow the Food Guide!
This list was designed to make it easy for you to choose the right foods. Avoiding processed foods will help you on your way to accomplishing your various health and wellness goals.

Your Next Steps

1. Avoid processed sources of carbohydrates, especially from refined grains.

2. Continue to use the Food Guide to make the best food choices.

3. Understand and use the Glycemic Index (tomorrow’s lesson).

4. Balance healthy carbohydrate intake with healthy fat and lean protein. No one macronutrient is more important than another!

5Learn to identify added sugar: The next time you pick up a snack, take a look at the nutrition facts. Added sugars will be in the ingredients list. Also, keep an eye out for sugar’s other names: corn syrup, high-fructose corn syrup, maltose, dextrose, fructose, sucrose, honey, molasses, maple syrup, and anhydrous dextrose.

 Identify high sugar foods in your diet: Think about the foods you like to eat. What sweets do you enjoy? Do you like to have a can of soda nearby? Do you always have dessert after dinner? Does eating a piece of chocolate often lead you to eat the whole box? Identifying the high sugar foods you tend to eat allows you to make informed strategies to avoid them in the future.

7. Find alternatives to sugary food: Find foods to replace the sugary snacks you usually eat. Drink unsweetened tea instead of soda. Serve fresh fruit for dessert instead of baked goods. Drink a protein shake instead of eating your morning doughnut. The more you rely on low- sugar alternatives, the easier it will be to avoid sugary foods.

8. Be wary of processed foods: Highly processed foods are notorious for adding sugar, even foods you wouldn’t expect. Frozen meals, crackers, salad dressing, tomato sauce, BBQ sauce, flavored yogurts, and foods that are marketed as “diet” or “low-fat” are all surprising sources of added sugar. Be vigilant about reading labels, and avoid processed and packaged foods whenever you can.

9. Stay hydrated: If you reach for sugar to give you a quick boost of energy, try a different approach. Energy slumps often come from dehydration. Keep them at bay by staying properly hydrated.

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