Sugar Alcohol on Keto: The Good and the Bad

Sugar alcohol is a class of artificial sweetener that is extremely popular within the low-carb community.

First marketed to those with diabetes, their low glycemic effect on blood glucose levels allowed them to be quickly adopted by the Atkins and keto crowd.

In fact, in 2002, Dr. Atkins added them to the list of acceptable sweeteners for those doing Atkins.

Today, Atkins Nutritionals, Inc., continues to recommend their use, provided you stay within their sugar alternative guideline of three servings per day.

But what about those doing keto?

In general, ketogenic diets come with fewer restrictions than Atkins. So you have to pay more attention to the safety factors and side effects, since the amount you eat won’t be limited.

You’ll also need to know how they affect your blood glucose level, insulin secretion, and weight loss.

If you want to successfully carve off the pounds, it’s also a good idea to have a clear understanding of which types of sugar alcohol are best to use and what sugars should be completely avoided on keto.

Despite the marketing claims, not all sugar alcohols are alike.

Some do affect your blood glucose level and, as such, they will adversely affect your ketogenic diet if you eat too much.

What is Sugar Alcohol?

Sugar alcohol is a form of carbohydrate that contains some of the same characteristics as sugar and alcohol, but it is not a sugar or an alcohol.

These sugar alternatives are polyols that are naturally found in various forms and artificially produced by manufacturers from sugar and starches.

Processes used to turn the base product into a crystalline powder will vary from manufacturer to manufacturer, but generally include fermentation, extraction methods, or enzymatic action.

Cornstarch is the most popular starter, but these sweeteners can also be made from:

  • Wheat
  • Leftover sugarcane stalks
  • Birch wood
  • Corncobs
  • Sugar beets
  • Corn syrup

Since sugar alcohols are a carbohydrate, they are eventually turned into glucose during digestion, but most forms except erythritol are not absorbed well.

Little glucose actually hits the bloodstream in healthy individuals because they are not broken down into glucose during digestion.

They pass into the colon in their original form.

This absorption defect is to the dieter’s benefit, making this form of sugar alternative extremely low in calories when compared to regular sugar.

However, the lack of calories doesn’t make them a free food. Some of these sweeteners still contain a hefty amount of carbs.

Why are Sugar and Sugar Alcohols Added to Food?

Humans are born with a preference for sweetness in foods.

According to the American Journal of Clinical Nutrition article, “Defining and interpreting intakes of sugar,” the amniotic fluid in the womb and a mother’s breast milk are both sweet.

Sugar has also been used as a preservative, along with salt, for centuries.

But its use in foods is for more than just sweetness.

The properties of sugar add bulk to baked goods.

Sugar helps products retain moisture, provides a palatable texture and aroma and enables the end product to brown well.

Sugar affects the size of the crumb and provides consistency.

In yeast-based applications, sugar feeds the yeast, so bread and rolls can rise, making them soft and fluffy. Sugar also inhibits crystallization.

Unlike other sugar alternatives, sugar alcohols do not lose their sweetening power during cooking and baking.

They are extremely heat stable. But sugar alcohols are also added to foods for more than just sweetness.

They add volume to baked goods, retain moisture, and improve the texture of the finished product, making keto baked goods come out closer to the products they’re trying to imitate.

Sugar alcohols also feed yeast making sugar-free bread softer and more palatable.

Low-carb recipes made with sugar alcohol are comparable to recipes made with real sugar. It’s hard to tell the difference.

Sugar Alcohol Vs Sugar: Difference

Unlike traditional sugar, recipes made with sugar alcohols can result in a cool sensation, due to crystallization, giving the finished product a minty taste.

Although they caramelize like sugar, making them a good alternative for low-carb candies and sweet sauces, sugar alcohols do not brown very well in the oven.

The finished product won’t look the same as a product made with sugar.

In addition, sugar alcohols come with a wide degree of metabolic tolerance.

To metabolize sugar you need a healthy insulin response to get the sugar into your body’s cells. Otherwise, your blood glucose level will go too high.

On the other hand, sugar alcohols are not fully absorbed like sugar, so they have less of an impact on blood glucose.

They will slowly raise blood glucose levels, requiring less insulin to metabolize.

Sugar alcohols also contain fewer calories than sugar, have a different chemical structure, and do not taste as sweet as sugar does. (2)

Benefits of Sugar Alcohol

When sugar alcohol first became available to the public, many believed it had no impact on your blood glucose level, so it was marketed to diabetics.

Over the years, scientific research hasn’t been able to back up the claim.

Today, marketing is more likely to stress the benefits that sugar alcohols have on oral health.

Where bacteria that live in the mouth will quickly and ravenously feed on sugar, bacteria doesn’t feed on sugar alcohol.

You are much less likely to suffer from tooth decay.

Sugar alcohols do affect your blood glucose, but not as dramatically as regular sugar does.

The effect on blood glucose is much less because they are difficult to digest.

For example, unlike other sugar alcohols, erythritol is almost fully absorbed into the bloodstream, but isn’t digested at all, so it passes out of the body in its original form in the urine.

Other sugar alcohols, such as sorbitol or xylitol are partially absorbed, and the part absorbed is broken down into glucose.

The degree to which your blood glucose level is affected depends on how much of the substance you can absorb and break down.

Less break down equals a slower rise in blood glucose, which makes sugar alcohols a good alternative for those with diabetes, metabolic syndrome, insulin resistance, or doing keto, but some forms of sugar alcohol are better than others.

There is a lot of variability in the number of digestive upsets and side effects of any particular sugar alcohol.

Side Effects of Sugar Alcohol

The most common side effect of eating too much sugar alcohol is digestive upset and a laxative effect.

Other common side effects include:

  • flatulence
  • stomach cramping
  • rumbling in the intestines
  • colic disturbances
  • bloating and swelling
  • increased frequency of bowel movements
  • diarrhea or loose stools

Sometimes, these side effects can be minimized by taking a smaller dose several times throughout the day, instead of all at once, but this isn’t always possible.

The kind of sugar alcohol you eat and your individual rate of absorption will determine how much you can handle on a daily basis.

Many people doing keto cannot handle any sugar alcohol at all, while others seem to be able to eat as much as they want without side effect.

Where you fall on that continuum is a matter of personal individuality. There’s no way to know ahead of time how you will react to these sugar alternatives.

What Kinds of Sugar Alcohol to Take During Keto?

There are dozens of sugar alcohol products available to the public, but the most popular ones found within the keto community are as follows:

Sorbitol: Sorbitol is not ordinarily purchased or used as a bulk or liquid product.

It is frequently found in diet pancake syrups, which can be used to sweeten sauces, baked goods, and vegetables.

Manufacturers also use sorbitol to sweeten low-carb ice cream, toothpaste, mouthwash, chewing gum, and candy.

Xylitol: Advertised for its oral health benefits and added in keto gums, this zero-calorie sweetener is available as a crystalline bulk product or in individual packets.

Isomalt: This sugar alcohol comes in white. brown, and powdered crystalline varieties, as well as a liquid syrup that is almost all fiber.

It’s frequently used in low-carb protein bars.

This type of product is only half as sweet as sugar, so you’ll need to use twice as much or combine it with another sweetener for a synergistic effect.

Maltitol: Most common sugar alcohol used by manufacturers, due to its properties being so closely related to real sugar.

It has the ability to make foods come out creamy and smooth.

Almost as sweet as sugar, you don’t have to use as much as other sugar alcohols, but maltitol seems to be the one least tolerated by those doing keto.

Erythritol: This is the most popular sugar alcohol among long-term dieters due to its extremely low glycemic index, small calorie load, and tolerance factor.

Since it’s almost fully absorbed by the body and then eliminated in the urine, unchanged, only a few keto dieters react adversely to erythritol.

It does have a cooling effect and tends to crystallize in the finished product if you use too much.

In addition to the above sweeteners, some popular products combine erythritol and stevia together, but these products are a bit misleading.

Many of these combo products only use traces of stevia, just enough to be able to place stevia on the package label.

While marketing stressing the stevia content of the product, they are mostly erythritol.

Which Sugar Alcohol is Best for Keto Dieters?

If you are diabetic, and need to keep your glycemic load down as much as possible or have insulin resistance or metabolic syndrome, erythritol is the best out of the available options.

It is lowest on the glycemic index, lowest in calories, and doesn’t cause as much digestive upset as the other choices.

This is also why erythritol seems to be the product of choice for most keto dieters, as well. However, which ones are best for you depends on your particular metabolic health.

Not everyone doing keto is insulin resistant.

For those who aren’t, all of the sugar alcohols listed above, including maltitol, are acceptable and beneficial for a ketogenic diet.

How to Count Sugar Alcohol on Keto?

Since sugar alcohol is partially digested, you’ll want to partially count the carbs in all products, except for maybe erythritol.

The Diabetes Teaching Center at the University of California in San Francisco offers the following advice on how to count sugar alcohol:

“When counting carbohydrates for products made with sugar alcohols, subtract half of the grams of sugar alcohol listed on the food label from the total grams of carbohydrate.”

This is what many long-term keto dieters already do, but if you’re new to a ketogenic diet, you might have fallen into the trap of assuming that sugar alcohols are zero carbs.

They aren’t.

Final Thoughts

The most important thing to remember when experimenting with sugar alcohols, especially during keto, is that these alternatives are not free foods.

While lower in calories than regular sugar, most sugar alcohols still contain a decent amount of carbohydrate that will affect how quickly the weight comes off.

Erythritol is an exception to this, at 0.2 calories per gram and zero on the glycemic index, but all sugar alcohols need to be used wisely and with care. Even erythritol.

Take it slow.

Experiment with only a little bit of sugar alcohol at a time.

Effect on blood sugar is less than real sugar, so insulin needed will be less.

However, the rate at which a sugar alcohol is absorbed and broken down into glucose determines how much of a rise you’ll get.

It’s totally possible to kick yourself out of ketosis by using too much sugar alcohol, especially if you’re in the habit of reaching for sugar-free products without reading the ingredients on the package.

Sugar alcohols are found in a wide variety of sugar-free products, and you won’t know they are in there unless you read the ingredients.

Sweeteners on keto are a good way to keep yourself compliant to the diet’s rules, but insulin resistance isn’t the only factor to consider. You’ll also have to weigh in your intestinal health.

Due to digestive upsets and most of the other side effects that tag along with sugar alcohols, they are not appropriate for keto dieters who have irritable bowel syndrome, inflammatory bowel disease, or other intestinal disorders. (2)

In addition, you don’t want to ignore the sugar substitute problem all together, even if you can’t tolerate sugar alcohols. On keto, you want to avoid:

  • white and brown sugar
  • honey
  • molasses
  • corn syrup
  • high-fructose corn syrup (HFCS)
  • fructose
  • agave

Although, marketed as a natural product that’s good for diabetics and those with insulin resistance, agave syrup or nectar is just a highly refined form of HFCS.

While it might be okay in tiny doses, it’s not really a keto-friendly food. For the best success on keto, stick with keto-friendly foods.

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