Have you seen that Food Babe video and other "exposés" on cellulose circulating around the Internet? Inevitably, these reports note that it's derived from sawdust.

Cellulose is a common food additive used to stabilize, thicken, emulsify and add bulk to processed foods. You'll find it in lots of low-fat items, including baked goods, dressings, dairy products and deli meat. It’s there to give the food the same mouth feel of its full-fat counterpart.

A form of cellulose helps create lower-fat yet crunchier fried food. Cellulose is also used as an anti-caking agent to keep products like pre-shredded cheese from clumping. You'll find it in organic products as well as conventional ones.

So what's all the fuss? Well, those claims that you’re probably eating sawdust are true. And while that might not sound appetizing, it's probably harmless.

Related: Food Additives: Are They Safe, or Can They Make Us Sick?

What exactly is cellulose?

Cellulose is a building block of all plant cells and fiber. So if you're eating a whole-food diet with plenty of fruits, vegetables, legumes, seeds and whole grains, you're eating cellulose. It's an insoluble fiber, which means it passes through your system undigested and helps keep you regular. Getting plenty of fiber, both insoluble and soluble, from whole foods helps slash your cancer risk.

But cellulose is also found in wood pulp — yes, the same stuff used to make paper — and this is the cheap source used in processed food. Manufacturers use this type of cellulose to bulk up foods (without adding calories) as well as improve texture. Cellulose often takes the place of other, pricier ingredients, such as oils and flour.

The use of cellulose isn't limited to food. It's also found in some cosmetics and medications. It may one day be used to create cheap biofuel for cars and, combined with stem cells, to repair cartilage in people with osteoarthritis.

The Food and Drug Administration (FDA) lists cellulose as "generally recognized as safe," or GRAS. However, the FDA does note that using cellulose to bulk up foods may reduce their nutritional value (since the additive is replacing something else), and that, if consumed in large amounts, cellulose can have an unwelcome laxative effect.

Related: The Truth about Carrageenan

An obesity connection?

Until now, there has been no evidence that your body knows the difference between cellulose from sawdust and cellulose from a legume. But a new Georgia State University of mice study suggests cellulose and other common emulsifiers used in processed foods may contribute to inflammatory bowel disease and metabolic syndrome in mice. Researchers suspect the emulsifiers reduce the diversity of gut bacteria, which may trigger obesity, glucose intolerance and, in some, inflammatory bowel diseases such as colitis.

It's far too soon to know whether these findings in lab animals translate to people, but if you want to avoid cellulose as a food additive, choose whole foods over processed foods. And when you do buy processed food, check the ingredients. Cellulose, like other food additives, must be listed on the label.

Alison Ashton is a freelance food writer, recipe developer and Cordon Bleu-trained chef based on Los Angeles.