An essential guideline on the ketogenic diet is to keep carb intake low, which is necessary for ketosis. However, you may be wondering if you can eat healthy low-carb grains and still stay in ketosis.
This article will help you clarify the difference between types of carbs and whether or not complex carbohydrates have a place in your low-carb diet.
What Are the Different Types of Carbohydrates?
Carbohydrates — along with fat and protein — are a macronutrient. Carbs are broken down by the liver into glucose, your body’s preferred energy source. There are three types of nutrients referred to as carbohydrates: starch, fiber, and sugar[*].
Carbohydrates are also divided into two categories: simple and complex[*].
Sugar is a simple carb, while starch and fiber are complex carbs. Whether a food item is classified as a simple or complex carbohydrate depends on how many sugar molecules it contains[*].
Simple carbohydrates are made up of one or two sugar molecules. Monosaccharides, like fructose (the sugar found in fruit) and glucose, are made up of one sugar molecule. Disaccharides, such as lactose (the sugar in milk) and sucrose (table sugar), are made up of two[*].
Simple carbs come from:
- Added sugars: White sugar, brown sugar, honey, agave nectar, maple syrup, powdered sugar, and high fructose corn syrup.
- Naturally occurring simple sugars found in fruits and milk.
Empty-calorie foods like soda and candy give simple carbohydrates a bad reputation, and it’s advised to eliminate them from any healthy diet.
These empty calories are also found in refined foods like white rice and white flour, which have been stripped of most of their nutrients. They only contain sugar and no starch or fiber, which may result in massive blood sugar spikes when you consume them.
Simple carbs are fast-acting, as they’re absorbed into the bloodstream almost immediately[*].
When referring to low-carb grains like steel-cut oats, whole wheat bread, and wild rice, you are referring to complex carbohydrates. Because of their fiber content, they typically have fewer net carbs than simple carbs.
Complex carbohydrates are made up of three or more sugar molecules, called oligosaccharides or polysaccharides, and they’re absorbed by your bloodstream more slowly than simple carbohydrates[*].
Complex carbs come in the form of:
- Starchy veggies: Potatoes, corn, parsnips, sweet potatoes, etc.
- Legumes: Lentils, chickpeas, black beans, kidney beans, etc.
- Whole grains: Bread, breakfast cereals, bulgur, quinoa, rice, etc.
What’s Better: Simple or Complex Carbs?
When it comes to carbs, you can’t really label one as “the best carb.”
There are three nutrients that makeup carbohydrates: sugar, starch, and fiber. These three nutrients can be found within a single food. In fact, it’s quite rare to find a type of food in nature that contains just one of the three.
Sweet potatoes, for example, are a complex carbohydrate commonly referred to as a starchy vegetable, but they also contain fiber and sugar. Likewise, berries are a simple carbohydrate and contain sugar, but they’re also a great source of fiber and important antioxidants.
Whether a carbohydrate is classified as simple or complex shouldn’t determine whether that carb is good or bad. Instead, you should look at how much sugar, fiber, and starch are present, and what kind of effect it will have on your blood sugar levels.
How Starch Is Broken Down During Digestion
Starches are a complex carbohydrate, made of many glucose units bonded together[*].
Just like sugar, starch is broken down during digestion into glucose to be used for energy. Starches come from whole foods like brown rice, corn, white potatoes, peas, beans, oats, whole grain bread, and whole wheat pasta.
If you’re familiar with your keto food list, you’ll quickly realize none of the above foods are keto-friendly.
Even though complex carbs (like starch) have a better reputation in most mainstream health circles and are considered healthy foods, your body processes starch just like sugar. Both are transformed into glucose for energy, which inhibits the production of ketones for energy (ketosis).
How Fiber Works
Fiber is a complex carbohydrate found in plant foods. Good sources of fiber include non-starchy vegetables, fruits, nuts and seeds, beans, and whole grains. No-carb foods like cottage cheese, salmon, ground beef, and other animal products, do not contain fiber.
Dietary fiber plays a vital role in the proper function of your gastrointestinal system, such as promoting healthy bacteria growth in your gut and aiding digestion. It also has great health benefits and has been shown to aid weight loss and decrease your risk of colon cancer, weight gain, heart disease, and type 2 diabetes[*][*].
There are two kinds of fiber[*]:
- Insoluble: It helps move food quickly through the stomach and intestines, regulating bowel movements, and preventing constipation. Examples are bran, seeds, vegetables, brown rice, and potato skins.
- Soluble: This type of fiber helps slow digestion and lower blood glucose and cholesterol levels. Examples include fleshy fruit, oats, broccoli, and dried beans[*].
Low-Carb Grains: Net Carbs vs. Total Carbs
When considering whether low-carb grains have a place in your diet, you need to look at how many net carbs they contain and not just at the total grams of carbohydrates.
Fiber is the differentiating factor between net carbs and total carbs.
Since fiber is indigestible, and not broken down into simple sugars like starch and sugar, it doesn’t affect your blood sugar levels. To calculate how many net carbohydrates are in a certain food, use this formula (in grams):
Total Carbohydrates – Total Fiber = Net Carbohydrates
For example, if a particular food contains 20 grams of total carbohydrates and 12 grams of fiber, the net carb count would be 8 grams.
Use the free Perfect Keto macro calculator to help you stay on track.
Which Low-Carb Grains Won’t Kick You Out of Ketosis?
You probably know by now that the average person needs to stay within 25-30 grams of net carbohydrates to maintain ketosis. This is however a relative guideline. While some people may get kicked out of ketosis when they consume more carbs, for others that might not be a problem.
The easiest way to find out is by experimenting and introducing a little portion of carbs in your diet, and then test your ketone levels. You may find out that you’re particularly sensitive to certain types of carbs, while others have no effect on your ketosis state.
Rather than selecting your carbs simply by their simple or complex nature, it’s important to learn and dive deeper into the nutritional breakdown of each food.
Since you’ll be cutting down or restricting certain food groups on a ketogenic diet, it’s important to make sure you’re getting all the vital vitamins and minerals for the proper function of your body.
If you do decide to introduce a small number of carbs in your meal plan, make sure that they complement your nutritional needs by being as nutrient-dense as possible.
Low-Carb Grains and Glycemic Index
When determining whether a low-carb food may inhibit ketosis, there’s one final measurement you should keep in mind: its glycemic index.
The glycemic index (GI) measures how much a particular food raises your blood sugar (glucose) levels after eating[*].
The index ranks on a scale from 0 to 100, with 0 GI foods — such as healthy fats, high-protein foods, and low-carb veggies — having no effect on your glucose levels, and 100 GI foods spiking blood sugar levels astronomically — like high-carb foods.
For example, refined grains like white bread and white rice hold a ranking of 75 and 73 respectively, while a sweet potato holds a ranking of 63[*].
Understanding Low-Carb Grains
Classifying a carbohydrate as “good” or “bad” would certainly make things easy, but it’s not the case when talking about low-carb grains.
To understand whether a food item may inhibit ketosis, learning more about the nutritional value of that food is crucial. Considering dietary fiber and net carbs is important, but nutrient profile and healthy fat content are also vital factors that make for a varied and balanced keto lifestyle. Understanding where a food ranks on the glycemic index is another great indicator.
As always, there is only one sure way to know whether a certain food will inhibit ketosis, and that’s to test your ketone levels.
Read more about grain-free and gluten-free substitutes:
Try these delicious keto-friendly recipes that can replace regular high-carb grains: