When checking the ingredients list of packaged foods, you might run into an ingredient called vegetable glycerine and wonder what it is. Vegetable glycerine (aka glycerol or glycerine) is a sugar alcohol synthetically derived from plants, such as soybeans, coconut oil, and palm oil. 

In its natural form, glycerine is actually a molecule that is produced in the body from glucose, protein, pyruvate, and other substances. The body produces it on its own so you don’t need to eat glycerine. Glycerol works to bind together triglycerides in the body, which are important for storing energy and are made up of three fatty acids that are bound together. 

When you use up glycogen in the body, which is stored glucose, glycerin can be converted into glucose to fuel your body. So glycerin overall is generally considered safe up to five grams per kilogram of body weight.

Vegetable glycerine is found in many different kinds of consumer products because of its uses as a sweetener, moisturizing agent, medical aid, and preservative with properties of being nontoxic, colorless, odorless, and sweet. Products that include vegetable glycerine include food, medical ointments, soap, shampoo, toothpaste, skincare products, an even antifreeze.   

One of the drawbacks of vegetable glycerine is that it is a carbohydrate and is included in many processed foods as a sweetener, so it raises blood sugar. So if you are on the keto diet, you have to be aware of this fact and monitor eating foods that contain vegetable glycerine and determine whether it is impacting your blood sugar levels and state of ketosis. 

Other side effects of vegetable glycerine include fluid retention in the body, because it draws water into the intestines and body tissue. This can lead to short term weight gain from increasing water weight. It can also lead to overhydration when drinking too much water combined with increased fluid retention, causing a dilution of sodium levels in your blood, called hyponatremia. This will result in an electrolyte imbalance and cause symptoms such as muscle cramping and various other physical ailments. 

Although vegetable glycerine is generally considered safe to eat, it is not technically a ketogenic ingredient and may negatively effect some people on their diets.  One way to make sure you are avoiding vegetable glycerine is to eat whole, organic and unprocessed foods. This will ensure that you are avoiding synthetic ingredients in the foods that you are eating. Also make sure you are always checking the ingredients list of foods that you are purchasing at the supermarket to confirm that nothing you are eating will negatively effect your diet and health. 

This is a tough one, because we get conflicting opinions on the topic of soluble corn fiber (SCF), also known as resistant maltodextrin, which is different from regular maltodextrin. Although this substance is used by many so-called health food companies, we should be really examining whether it is a substance that we should be eating on a keto diet. Soluble corn fiber is super cheap and used by food companies to thicken and preserve processed foods. It also causes lower spikes in blood glucose than IMO’s, which is why Quest Nutrition replaced IMO’s in their foods with soluble corn fiber. Some people say soluble corn fiber is allowed on a keto diet because it is not the same as corn, but rather fiber that is extracted from corn with a low net carb profile.   

In general, dietary fiber, which is found mostly in vegetables, fruit, legumes and grains, is known for helping bowel movements, lowering cholesterol, and balancing gut bacteria. All fiber is non-digestible, and soluble corn fiber is no exception. However, soluble corn fiber, unlike dietary fiber, actually spikes your blood glucose levels. Compared to white sugar though, it is lower on the glycemic index at 25, compared to white sugar, which is 100. Even so, this is enough to possibly knock you out of ketosis. Also soluble corn fiber is not a natural substance. It is processed from corn syrup, which is already a chemically processed substance. 

Are there any benefits to eating soluble corn fiber? Some say it acts as a prebiotic fiber, but there are plenty of other natural options that work better. Some better high fiber and natural foods include: avocado, broccoli, cauliflower, zucchini, eggplant, coconut meat, etc. 

All in all, low amounts of soluble corn fiber might not do damage to your diet, but in sufficient amounts it could cause harm. So it is best to avoid soluble corn fiber and other substances of similar nature. Also, different people have different body chemistries, so everyone needs to experiment with different foods and ingredients and analyze how it effects them to determine what is beneficial for them and what is not.  

When starting a ketogenic diet, we have to train ourselves to study the ingredients of the foods we eat, because food labels alone can be misleading, as the FDA doesn’t have the strictest guidelines on the true accuracy of these food labels. That’s why when you run into an ingredient that you’ve never heard of or that sounds weird, it’s time to be detective and do some research into it. 

When searching for keto-friendly products, we often find an ingredient called soluble or prebiotic tapioca fiber in the ingredients list. At first glance this may seem like a natural ingredient and not worth fretting about, but when digging deeper, it can be surprising what you may find.

For example, there seems to be a link between soluble tapioca fiber and isomaltooligosaccharides (IMO) on food labels. More directly speaking, many companies are including IMO’s in their products and calling it soluble tapioca fiber, most likely because both soluble tapioca fiber and IMO’s are created from corn and tapioca starch. This is problematic, because real tapioca fiber is not the same as IMO, which means it is incredible confusing and difficult to differentiate between the two on a food label. (For the sake of consistency and avoiding confusion, we will refer to IMO’s as soluble tapioca fiber for the rest of the article.)

The name soluble tapioca fiber is also misleading, because IMO’s are not actually dietary fiber and actually effect your blood glucose levels. There have been studies that show IMO’s can spike blood glucose levels to the same extent as glucose and dextrose. Similarly, products containing IMO’s can spike blood glucose the same way regular sugar does.    

So why do companies use (IMO) tapioca fiber in their products? Soluble tapioca fiber acts as a mild sweetener and thickener, improving the consistency of food products. It is also half the cost as soluble corn fiber. Many companies are also advertising their products as no-sugar-added and then adding soluble tapioca fiber instead, which has the same effect as sugar. So we can see how some companies are using this ingredient as a substitute for sugar, even though it has the same effects as sugar. In fact, a few years back, Quest Nutrition replaced IMO’s in their products with soluble corn fiber, which can be a slightly better alternative. (We’ll talk about soluble corn fiber in another article.)   

Should we avoid soluble or prebiotic tapioca fiber on a keto diet? In large amounts, yes you should avoid it. In negligible amounts, this ingredient can be treated as regular sugar, which won’t impact you too negatively if you don’t exceed your carb limit. When compared to soluble corn fiber, soluble tapioca fiber will spike your blood glucose more significantly, and it does not act as a dietary fiber. So be cautious when you see this ingredient listed on the products that you buy, and do your own research. You can also test the effects that these ingredients have on your body by measuring your own blood glucose levels, and then you can analyze the results and come to a conclusion of whether to consume the products in the future or not.