I’ve heard it all as a nutritionist.  From recommendations for 75 plus grams of fiber a day for those with insulin resistance, to the idea that the human body needs no fiber at all.

What is the truth?

There is a relative consensus among functional practitioners that most of the population of the developed world has some form of insulin resistance, be they thin or overweight.  And there is a general consensus that the best approach to managing insulin resistance and its many related issues like obesity around the middle, diabetes and prediabetes, chronic acne, hormonal disruption, hypoglycemia, and many many others, is to reduce the glycemic load (the amount of sugar) taken into the body.

Research has shown again and again the lower carbohydrate diets are effective at reducing not just weight but body fat and creating healthier individuals with increased energy and metabolic improvements.  

Low carb diets range from beneath 150 grams of carbohydrate a day to less than 25 grams a day, depending on the person, their needs and concerns, the practioner’s preference, and a range of other considerations.

But recently the ketogenic and very low carbohydrate diets have made a comeback.  Research shows them to be safe and effective for many people if done correctly.  And if is the key word.

On a low carbohydrate or keto diet, fat or protein (sometimes both) are emphasized while carbohydrates are very limited.  This produces great improvements in blood sugar.  Less sugar going in, less insulin being pumped out.  Many people find relief from obesity and related conditions in a rather quick window of time.

But the dangers of these diets are not to be ignored.  And for as much success as some people have, many others find themselves feeling alienated when these diets just don’t seem to work for them.  

One of the key issues in a low carbohydrate diet is the lack of fiber.  It is generally agreed upon that the human body needs at least 25 grams of fiber a day to maintain proper bowel function and intestinal health.  And fiber isn’t just about poop!

But while I’m on the subject of poop, having regular bowel movement is SO IMPORTANT.  It’s not just optional.  It’s a major sign of the overall health of the entire body.  And without regular, healthy bowel movements, we cannot properly detoxify our bodies from excess hormones, cholesterol, and other scary things that get shoved into the gastrointestinal tract for disposal.  Without proper bowel movements, these things can get reabsorbed and cause havoc (if we have dysbiosis and excess beta-glucuronidase activity-something for another post).  

Here are just some of the things that fiber is known to do:

• Slows the absorption of sugar from food and thus the release of insulin
• Make you feel full so you don’t overeat
• Lower blood cholesterol and improve removal of excess lipids from the diet
• Improve fecal bulk and reduce constipation AND diarrhea (depending on the underlying issue)
• Help with the removal of excess hormones by improving fecal transit time
• Fermentation process helps improve gut bacterial health, a key to having a healthy immune system

But for those consuming less than 25 grams of carbohydrate a day, getting 25 grams of fiber is going to be impossible.  That is, unless they use NET carbohydrates instead of TOTAL.

But what does that mean?

This is one of major mistakes that those new to low carbohydrate diets do.  They look at the back of a label and see that it says 10 grams of total carbohydrate.  They therefore assume they should subtract 10 grams from their daily allowance.  But what they should really do is look underneath the total count to the fiber.

Both soluble and insoluble fiber, listed below the total carbohydrate count, have no effect on blood sugar.  

Essentially, fiber is a substance that passes right through you.  On the way, it grabs stuff you’d rather get rid of and helps pull it out of the body, but it has no effect on how much insulin you release at all.  In fact, it actually slows the release of insulin, making you feel full longer, and helping provide you with much more steady energy.

The temptation on a low carb diet is to save those 25 grams of carbs for a “treat”, maybe a bite or two of sweet potato or some corn.  Instead, with the very little carbohydrate allowed on these diets, it is best to prioritize high fiber, nutrient dense foods like vegetables.  

A person with a 25 gram of carb daily allowance could potentially eat 4 servings of broccoli in a day when accounting for the fiber and while still not meeting the recommended 25 grams a day recommended by most major health professionals, would certainly get you much closer than having 25 grams of carbohydrate from sweet potatoes or oatmeal, not to mention a LOT more nutrition.

This is one of the reasons why I am not a proponent of most people eating a ketogenic diet long term unless their health history warrants it.  Certainly it can be beneficial for some subgroups of people, but overall I like to do it to aid in weight loss, and then transition to a higher fiber while still low glycemic diet that places a focus on lots of anti-inflammatory nutrients.

For those clients who do follow ketogenic diets, I often have to recommend natural fiber supplements such as Biolax (find it here) in order to help keep the bowels moving. I’ve found this to work really well overall with most of my clients and it helps them maintain their ketogenic protocol without suffering constipation.