A Guide to Understanding Carbohydrates

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In the cereal aisle at my hometown supermarket I met a friend who blurted out that chasing carbohydrate clarity is exhausting. “Why don’t they just tell us how much sugar is added to this stuff?” she asked.  “How do I know if this is a good carb or a bad carb?”

This seems to be the question of the year, if not the decade. Like my friend, most people seem to have some level of confusion around carbohydrates. This guide should help clear the air and let you take action.

What foods contain carbohydrate?

Carbohydrates are found mostly in plant foods, with one exception: milk and foods made from milk. Milk contains a natural simple sugar called lactose. Lactose plays an important role in milk, making it taste good and enhancing the absorption of calcium.

Carbohydrates in plant foods are both simple and complex. The sweetness in fruit comes from the simple sugars fructose and glucose, and the fiber in fruit is a complex carbohydrate. There is a small amount of simple sugars in vegetables, depending on the specific vegetable, and the fibers are again, complex carbohydrates. Grains are full of starch, a complex carbohydrate, as well as fiber, and contain zero sugar. Simple sugar may account for a tiny bit of the carbohydrate in beans, but the carbs are predominantly starch and fiber. There are even small amounts simple sugars in nuts and seeds, which we think of as great sources of healthy fats and fiber.

The most common misconception about carbohydrate-containing foods is that if you have eliminated grains and sweets you have eliminated carbohydrate from your diet. It should be clear now that if you are eating plant foods, you have carbohydrate in your diet.

Healthy carbohydrates and why

Decades of research has made it abundantly clear that the less refined the food in your diet, the odds are that you will be healthier. There is nothing unhealthy about carbohydrates that come from whole foods like grains, beans, fruits and dairy. It is the refining of foods in our diet to highly refined flours, grains and sugars that has become harmful to our health. All kinds of simple and refined sugars and syrups, white flour, white rice, commercial baked goods, many packaged foods and snack foods, and alcohol, fill the shelves of our stores. Processed foods have been stripped of their important nutritional factors, including fiber. Because they lack fiber and phytochemicals, and have engineered flavors added, it is easy to eat huge quantities of calories without feeling full. Foods with processed carbohydrate are the ones you should mostly avoid.

Not surprisingly, people who eat the best types of carbohydrate tend to weigh less and have better control of blood lipids and carbohydrate metabolism when compared with those who eat predominantly simple sugars and refined starches. Increased whole-grain intake in particular is associated with decreased risks of obesity, coronary heart disease, type 2 diabetes, insulin resistance, and many causes of illness. Thus, by replacing nutritionally poor types of carbohydrate with the best, nutritionally rich ones, you gain better control over most of the physiological and metabolic risk factors associated with the development of obesity and chronic disease.

Finding the Added Sugar

If it’s the sugar added to foods rather than the small amounts of sugar naturally found in plant foods and dairy, how do we know how much sugar is added to foods? The United States Department of Agriculture was supposed to already be helping us with that information by the passage of a law that boxed foods had to post the amount of added sugar on the Nutrition Facts label. The deadline was originally July 2018, but that has been postponed to January 2020 for large food manufacturers, and January 2021 for somewhat smaller companies. Once implemented the label will be slightly updated, and “Added sugars,” in grams and as percent Daily Value, will be included on the label. (See graphic below)

Original vs. New Format – Infographics to Help Understand the Changes*



Since we have at least another year or two before we can easily see the amount of added sugar in foods, you can learn how to basically figure it out for yourself, just as I do, by following these basic guidelines. Every 1 teaspoon, or serving, of sugar contains 4 grams of carbohydrate and 16 calories.

Determining Added Sugar in Foods*

Cereals and Grains

Grains do not contain any sugar. By looking at the Nutrition Facts label on the side of a box of cereal such as Shredded Wheat, you’ll see 0 grams of sugar in a serving.

Therefore, the manufacturer adds any sugar contained in a cereal.

Most sweetened cereals  contain 8 grams of sugar per serving, which is the equivalent of 2 teaspoons of added sugar, and many contain much more. The exception is cereals with added fruit. Some of the sugar in these cereals comes from the fruit. Look at the ingredient label. If any kind of sugar is listed ahead of the fruit, you know that the greatest proportion of the added sugar is not from the fruit. The same concept goes for breads, crackers, and other grain products. Any sugar on the label is added in processing.

Milk and Yogurt

One cup (8 ounces, or 240 ml) of milk contains 12 grams of natural milk sugar, or lactose.

If you look at the Nutrition Facts label on a carton of milk, you will see that one serving (1 cup) contains 12 grams of sugar. Any amount of sugar above that is added, as in chocolate milk and other flavored milks.

Yogurt cartons are generally 6 oz (180 g). A carton of plain yogurt will contain about 12 grams of natural milk sugar. Anything above that is added sugar. Most yogurts are sweetened with at least 4 teaspoons of added sugar, and many use 6 teaspoons or more.

Fruit and Fruit Juices

A medium-sized piece of fruit contains about 15 grams of carbohydrate. Some of that is fiber, often 2 to 3 grams, and the rest is natural fruit sugar. When purchasing canned or frozen fruits and fruit juices, you must read the ingredients label to check for added sugar. Any amount of sugar above 15 grams for 1/2 cup (120 g) of canned or frozen fruit or 1/2 cup (120 ml) of fruit juice is added to the product.

Vegetables, Vegetable Juices and Soups

A medium-sized vegetable contains 5 grams of carbohydrate and no appreciable amount of sugar. Any sugar listed on the Nutrition Facts label is added to the product.


Obviously, water has no amount of natural sugar. So if you’re looking at the Nutrition Facts label on the side of a soft drink can, all the sugar is added, and it usually amounts to about 10 teaspoons (50 g) per 12-ounce (360 ml) can. Typical sport drinks contain about 12 grams of sugar per cup, equivalent to 3 teaspoons (15 g) of added sugar per serving. Some sport drinks report dosing in grams of carbohydrate or sugar on the label.

To determine your allowance for training, refer to the menu plans in chapters 15 through This same principle can be applied to most bottled beverages that do not contain any milk or fruit juice. When it comes to fruit juice concentrates added as sweeteners to beverages and foods, the juice is highly refined in the processing and is little more than sugar syrup. Ingredients such as white grape juice concentrate are virtually the same as added sugar.

*From Kleiner, SM, Greenwood-Robinson, M. The New Power Eating. Human Kinetics, Champaign, IL 2018, p. 275.

Fuel with Carbohydrate

When health is your goal you want to be as active as possible. Carbohydrate-rich foods are healthy because of the rich nutrient density of the whole foods. The carbohydrate itself is muscle fuel. Including whole or only lightly refined plant foods and dairy in your diet helps fuel physical activity and keep mood elevated. The higher the intensity and the longer the duration of your exercise, the more carbohydrate fuel that is required to keep you going.

While eating food is the best way to get in all of your body’s nutritional needs, when exercise is your goal you might find that turning to scientifically formulated carbohydrate sport fuels work best. Of course, these are used only around exercise. When counseling my athletic clients, I always recommend Vitargo, the fastest muscle fuel that is all complex carbohydrate starch, and zero sugar. You can match your carbohydrate fueling to each exercise bout, adjusting the scoops of Vitargo up or down depending on your fueling need. There is no bloat and no crash.

Think of your carbohydrate nutrition in two silos: food that nourishes your body and fuel that drives your exercise. Around exercise, the goal is not to get in wholesome nutrient-dense food that takes too long to empty from your stomach, it’s to fuel your exercise as comfortably and completely as possible. That’s why I like Vitargo.

Carbohydrates – they’re personal.

The conversation around carbohydrates is not an all or nothing approach. It’s much more nuanced, with lots of positive influences on your health and well-being. Personalizing your approach to the carbohydrate-rich foods and supplements in your diet based on your goals,  your activity and lifestyle will help you feel more empowered and secure with your choices.  

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