Carbohydrates: Sugar, Starch, and Fiber

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Carbohydrates: Sugar, Starch, and Fiber

This article will cover the basics of carbohydrates ("carbs"). The various types of carbohydrates found in food, why we need them and which types are better for our health.

What are carbohydrates and what are the different types found in food?

Carbohydrate is an umbrella term that includes all starches and sugars. Technically, carbs are molecules that contain single, double, or multiple sugar ("saccharide") units. Simple sugars contain only one or two saccharide units and are typically sweet tasting. Complex carbohydrates are thousands of saccharide units long and have a starchy taste. See below for examples of foods that contain mostly sugars or starch. After we eat sugars or starches, our blood glucose level rises. This signals our body to produce insulin (a hormone that removes glucose out of the bloodstream and into the cells for energy). Excess glucose will be stored as glycogen in our liver and muscle. If there is still excess glucose, it will be converted and stored as body fat. Eating too many calories from sugar or starch can cause weight gain. Also, a diet high in refined starches and added sugars is linked to a higher risk for cardiovascular disease.

Simple sugars Complex carbohydrates
  • Milk
  • Fruit
  • Honey
  • Juice
  • Syrup
  • Sugar
  • Starchy vegetables
  • Grains
  • Grain products (e.g. bread, pasta, crackers)
  • Legumes

All digestible simple sugars and starches eventually get converted to glucose in the body. Most types of cells use glucose as their main fuel source.

To learn more about how simple sugars and starches impact blood glucose and diabetes please read: "Tips for Managing Diabetes".

Carbohydrate Goal

Since most MyNetDiary members are trying to lose weight and/or manage their prediabetes or diabetes, MyNetDiary uses a macronutrient distribution to encourage intake of healthy proteins and fats while controlling carb intake. The goals are within the Acceptable Macronutrient Distribution Range for fat, carbohydrates, and protein developed by the Institute of Medicine of the National Academies. These ranges support intake of essential nutrients while also limiting risk of chronic diseases.

Macronutrient DRI: Acceptable Macronutrient Distribution Ranges MyNetDiary Goal
Fat20-35% of total calories35% of total calories
Carbohydrate45-65% of total calories45% of total calories
Protein10-35% of total calories20% of total calories

If you follow an eating pattern that requires a different macronutrient distribution range, then simply customize your macronutrient goals. You can customize your macronutrient goals on any device with a Premium membership. You can also customize your goals if you use the standalone Diabetes Tracker application.

Dietary Fiber: An important carbohydrate for health


Dietary fiber (or simply called fiber) is a type of carbohydrate food. It is considered a complex carbohydrate, however the human gut does not possess the enzymes needed to break apart the links between sugar units. Undigested fiber travels through our gut and while doing so, provides health benefits. Fiber encourages growth of healthful bacteria in our lower gut. Benefits come from two different types of plant fibers that are classified based upon whether or not they dissolve in water (soluble) or not (insoluble). It is important to consume both types of fiber for maximum health benefits.

Fiber Type: Insoluble

Benefits: Regularity (relieves constipation), lower risk of diverticulosis (gut pouches that get inflamed)
Food sources: Bran from grains/cereals, skins and seeds from fruits and vegetables, dried beans/peas, brown rice

Fiber Type: Soluble

Benefits: Helps reduce straining with excretion, binds cholesterol in the gut, and helps control the rise of blood glucose after a meal
Food sources: Fleshy part of fruits and vegetables, oats, dried beans/peas

How Much Fiber Is Enough?

The Dietary Reference Intake (DRI) for total fiber intake for adults is 14 grams per 1000 calories intake. This is also MyNetDiary's recommended goal. Some people prefer to use standardized goals for fiber intake so that when their calories intake is lower for weight loss, they still consume plenty of fiber.

Standard Fiber Goals:

The DRI is for total fiber, there is no breakdown by type of fiber. One simple way to meet your fiber goal is to eat three or more servings of whole grains and five or more servings of fruits and vegetables daily. Vegetables include both non-starchy and starchy types, as well as dried beans and peas. With this strategy, you consume a variety of healthful foods that provide both types of fiber. If you prefer lower carb eating, then focus on getting fiber from non-starchy veggies (e.g. artichoke, Brussels sprouts, broccoli), seeds (e.g. chia, sunflower seeds), and nuts (e.g. almonds, pistachios). You can learn more in MyNetDiary's blog post Great Food Sources of Fiber.

MyNetDiary Tip

You can select fiber as a nutrient to track. To customize your fiber goal, go to Plan section. You can view information about fiber as well as the recommended value. Show On Dashboard option lets you track the nutrient on Dashboard. Show In Log option lets you see the nutrient on food logging screens and in food reports.

Net Carbs

Net Carbs=Total Carbohydrate (g)-Dietary Fiber (g)-Sugar Alcohol (g)

Net carbs are not a type of carbohydrate found in food. Instead they are mathematically calculated by subtracting the dietary fiber (in grams) and the sugar alcohols (in grams) from the total carbohydrate (in grams) found in a food. Net carbs can easily be figured as long as the food label has gram information for these three nutrients. If a product does not contain sugar alcohols, then the MyNetDiary system assumes this value is zero when doing the net carb calculation. The term "net carbs" is not regulated by the FDA. The only carbohydrate information that is regulated is the information found in the nutrition facts label.

Many people like to track using net carbs since it is the lowest of all carb counts. However it underestimates the true digestible carb load as some amount of soluble or viscous fibers, although not digested in the small intestine, can be broken down in the large intestine, absorbed and then converted to glucose. If you are dosing meal time insulin based on a carbohydrate content of a meal, please talk with your health care provider or diabetes educator about using the American Diabetes Association's method for counting carbs. This will help you better match your insulin dosage with carbohydrates consumed and likely improve post meal blood sugars.

Sugar Alcohols

Sugar alcohols are low calorie sweeteners used in processed foods. They are lower in calories than sugar though are not completely broken down in the gut. Thus some people experience unpleasant side effects (such as gas, bloating and diarrhea) when consuming them . Some sugar alcohols can be broken down and converted to glucose. This is important to realize if you have diabetes and need to precisely count your carbohydrates. If you match your insulin to meal-time carbs, then consider using Diabetes Carbs for tracking (available with MyNetDiary Premium membership). You can learn more about carb counting in the Diabetes Basics article.

Current Sugar Guidelines

Sugar is a type of carbohydrate in food. Here are two recommendations concerning added sugars in the diet: one from the Dietary Guidelines for Americans 2015-2020 (USDG) and one from the American Heart Association. The American Heart Association published guidelines for added sugars in this article: Dietary Sugars Intake and Cardiovascular Health A Scientific Statement From the American Heart Association.

The American Heart Association's recommended limit for added sugars are:

The USDG has one recommendation for the general population - consume no more than 10% total calories from added sugars. For example, if you consume 2000 kcal, then your limit would be 200 kcal (50 grams) from added sugars per day.

Added vs. Natural Sugar?

The guidelines above specifically refer to added sugars: table sugar, honey, natural syrups (e.g. agave, maple, molasses, etc.), commercial syrups (e.g. high fructose corn syrup, etc.), and concentrated fruit sugars added to foods to sweeten or preserve. The naturally occurring sugars in milk, fresh fruit, unsweetened dried or frozen fruit, and 100% fruit juice are not considered added sugars. Artificial sweeteners and sugar alcohols are also not considered added sugars.

Total sugar grams listed on the Nutrition Facts panel include both naturally occurring sugars and added sugars. Added sugars grams are listed under total sugar on the Nutrition Facts panel for most packaged foods.

If you choose to select Sugars as a nutrient to track, just remember the value refers to total sugars, not added sugars. MyNetDiary uses a default goal of 25% total calories for Sugars.

MyNetDiary is looking forward to including "added sugars" as a nutrient to track when all food labels are required to list them. The new food label should be implemented for all packaged foods in 2021.

Hidden Sources of Added Sugars in "Healthy Foods"

It is easy to identify regular soda pop and energy drinks as examples of empty calories, but what about sugary foods and drinks that also have nutrients? Choose brands that have less sugar than their rivals or select unsweetened versions. Here are some otherwise nutritious foods that often have too much added sugar:

Sweet Tooth Tip

One teaspoon of added sugar is about 4 grams. If you add your own sweetener to unsweetened foods and drinks, you can control the amount you use. Also, you might find that using more spice can help you get used to a less sweet taste.


Carbohydrate containing foods fit into a healthy diet. When deciding which carbohydrate foods to include in your diet strive for those that provide nutrients while limiting fat, sodium, and added sugar. The simplest way to consume healthier carbohydrates is to choose unprocessed whole grains, starchy vegetables, fresh fruit, dried beans and peas, plain milk or non dairy beverage, or plain yogurt. If you can choose those types of foods instead of refined versions, then you should be able to meet your carbohydrate needs while also meeting dietary fiber while limiting added sugars, sodium, and excess calories.

If you have questions about this topic then ask them in the MyNetDiary community forum!

Last Updated on Jan 17, 2020

Jan 17, 2020
Katherine Isacks
Katherine Isacks, MPS, RDN, CDCES - Registered Dietitian and Certified Diabetes Care and Education Specialist (CDCES)

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