Carbohydrates: Sugar, Starch, and Fiber

  • 6 Minutes Read
  • May 14, 2018
Carbohydrates: Sugar, Starch, and Fiber

This article will cover the basics of carbohydrates (“carbs”) — what they are, why we need them, and which types are better for our health.

What Are Carbohydrates?

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.

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 our body. Most types of cells use glucose as their main fuel source. After we eat sugars or starches, our blood glucose level rises. This signals our body to produce insulin, a hormone, so that cells can take the glucose out of the bloodstream and use it 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 us to gain weight. Also, a diet high in refined starches and added sugars is linked to a higher risk for cardiovascular disease.

Sometimes people get confused as to how simple sugars and starches affect blood glucose. Please read “Tips for Managing Diabetes” at MyNetDiary if you would like more information about carbohydrates and 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 fats and protein 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 Acceptable Range* MyNetDiary Goal
Fat 20—35% of calories 35% of calories
Carbohydrate 45—65% of calories 45% of calories
Protein 10—35% of calories 20% of calories

* See Acceptable Macronutrient Distribution Ranges in DRI tables

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.


Fiber is a complex carbohydrate but 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 also 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.

I know that many people like to track using net carbs since it is the lowest of all carb counts, but it can underestimate the true digestible carb load. 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. Also, some sugar alcohols (low caloric sweetener used in processed foods) can be broken down and converted to glucose. If you need a more precise carb count, especially if you match your insulin to meal-time carbs, then consider using Diabetes Carbs for tracking (available with Premium membership or the standalone Diabetes Tracker app). You can learn more about carb counting in Diabetes Basics at MyNetDiary.

Fiber Type: Insoluble

Benefit: 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

Benefit: Helps reduce straining with excretion, binds cholesterol in the gut, and helps control 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.

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.

Current Sugar Guidelines

There are two recommendations concerning added sugars: 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:

Their recommended limits 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.

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.

Sugar grams listed on the Nutrition Facts panel include both naturally occurring sugars and added sugars. This will change when the new labeling law takes effect - added sugars will be listed. But for now, look at the ingredient list to see if your food contains added sugars. Names for added sugars are numerous - see What Are Added Sugars at USDA Choose MyPlate for examples.

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 food labels are required to list them. The new food label is supposed to be implemented by January 2020 unless the FDA extends the deadline again.

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:

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.


Healthful carbohydrates are 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 nondairy beverage, or plain yogurt. If you can choose those types of foods instead of refined versions, then you should be able to meet your fiber goals while also limiting added sugars, sodium, and excess calories.

If you have questions about this topic then ask them in MyNetDiary Community Forum!

Katherine Isacks
Katherine Isacks, MPS, RDN, CDE - Registered Dietitian and Certified Diabetes Educator (CDE)

Last Updated on May 14, 2018

Disclaimer: The information provided here does not constitute medical advice. If you are seeking medical advice, please visit your healthcare provider or medical professional.

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