The importance of fiber and sugar in our diets…

Why discuss fiber and sugar?

Fiber and sugar are the most misunderstood and often neglected part of any diet. When people talk about dieting or changing eating habits they center it around calories consumed, maybe break it down into macros for protein, fat and carb consumption, etc.  But one of the secrets to all of this is your fiber and sugar intake.  These two components are essential in how effective you digest what you eat and how your body burns fat.

Fiber primer, what is it and how does it work?

Fiber comes in the form of a carb. There are two basic types, soluble and insoluble although each can be broken down into sub-categories that we will not get into here.

Soluble fibers bind with fatty acids and slow digestion so blood sugars are released more slowly into the body. These fibers help lower LDL (bad) cholesterol and help regulate blood sugar (insulin) levels.  This is very important because those components is also what regulates your body from burning fat.  More on that later in the sugar section of his post.

Insoluble fibers help hydrate and move waste through the intestines and control the pH levels in the intestines. These fibers help prevent constipation and keep you regular.  Think of them as a scrub brush for your insides, cleaning out the linings of the intestinal walls. This is essential in order to increase the nutrient assimilation efficiency of the foods you eat.

What happens to fiber as it passes through you?

The stomach: Fiber is bulky so in the stomach it tends to make you feel full.  However, insoluble fiber moves out of the stomach fast unless there is fat, protein, or soluble fiber to slow it down.  Soluble fiber will slow down stomach emptying, especially when eaten with lots of fluid and some fat.  This is why soluble fiber tends to decrease the glycemic (level of sugar) effect of a meal – the contents of the stomach more gradually enter the small intestine, and from there, the blood.

The small intestine:  In the small intestine insoluble fiber tends to speed “transit time” up, and the soluble fiber slows things down.

The colon:  The colon is normally thought to be the place where water is removed from whatever is left from digesting the food, and the rest is moved along towards the toilet.  In reality, the colon has ten times the bacteria of all our human cells and this ‘friendly’ bacteria does many things.

In the colon vitamins are constructed especially vitamin K and some B’s. More minerals are absorbed, and short chain fatty acids are produced which many now believe is a contributor to keeping colon cells healthy and preventing conditions like colitis, colon cancer and regulating cholesterol.

How much fiber?

One thing to keep in mind about fiber is that the amount recommended per day is not influenced by gender, height or weight. Fiber is all about your digestive system and we all pretty much have the same digestive system.

As such, the recommended daily averages I have seen range from 25-40 grams per day. Why the difference? I think primarily it’s that 25 is the recommended low end minimum but there are studies that recommend more for various reasons most of which are for better cleansing of your digestive tract or to slow down insulin spikes which equates to increasing fat burning capability.

One thing to take note of is that canned fruits and vegetables have most of their fiber stripped in order to preserve shelf life. The same is true for most items frozen. They are also pumped with sugar or similar derivatives for the same purpose. So it is very hard to get fiber naturally but the best way is to buy fresh produce.

The average American diet is very low in fiber.  With most people that I train, when we add it up it is usually below 15 grams per day. This can explain many of the health problems we have in this country.

Regardless of how much fiber you consume, DRINK PLENTY OF WATER! You do not want the fiber to bind in your digestive system.

What are some fiber sources?

Below is a nice table I found on the internet that gives you the type of fiber, whether it is soluble or insoluble, what source you can get it from as well as health benefits.


Types of Fiber Soluble or Insoluble Sources Health Benefits
Cellulose,some hemicellulose Insoluble Naturally found in nuts, whole wheat, whole grains, bran, seeds, edible brown rice, skins of produce. “Nature’s laxative”: Reduces constipation, lowers risk of diverticulitis, can help with weight loss.
Inulin oligofructose Soluble Extracted from onions and byproducts of sugar production from beets or chicory root. Added to processed foods to increase fiber. May increase beneficial bacteria in the gut and enhance immune function.
Lignin Insoluble Found naturally in flax, rye, some vegetables. Benefits heart health and possibly immune function. Use caution if celiac or gluten intolerant.
Mucilage, beta-glucans Soluble Naturally found in oats, oat bran, beans, peas, barley, flaxseed, berries, soybeans, bananas, oranges, apples, carrots. Helps lower bad LDL cholesterol,


reduces risk of coronary heart disease and type 2 diabetes. Use caution if celiac or gluten intolerant.

Pectin and gums Soluble (some pectins can be insoluble) Naturally found in fruits, berries, and seeds. Also extracted from citrus peel and other plants boost fiber in processed foods. Slows the passage of food through the intestinal GI tract, helps lower blood cholesterol.
Polydextrose polyols Soluble Added to processed foods as a bulking agent and sugar substitute. Made from dextrose, sorbitol, and citric acid. Adds bulk to stools, helps prevent constipation. May cause bloating or gas.
Psyllium Soluble Extracted from rushed seeds or husks of plantago ovata plant. Used in supplements, fiber drinks, and added to foods. Helps lower cholesterol and prevent constipation.
Resistant starch Soluble Starch in plant cell walls naturally found in unripened bananas, oatmeal, and legumes. Also extracted and added to processed foods to increase fiber. Helps weight management by increasing fullness.
Wheat dextrin Soluble Extracted from wheat starch, and widely used to add fiber in processed foods. Helps lower cholesterol (LDL and total cholesterol), reduces risk of coronary heart disease and type 2 diabetes. Avoid if celiac or gluten intolerant.


Now lets move on to sugar and how it works…

When we eat carbs its converted into blood sugar or glucose which is where we get our energy. Our blood sugar level effects how hungry and energetic we feel. It also determines whether we burn or store fat.

Insulin is a hormone created in the pancreas that transports blood sugar into our body’s cells where it is used for energy. When we eat simple carbs (anything rich in sugar or its derivatives and whose fiber has been stripped away) the pancreas goes into overtime producing the insulin that is necessary so the blood sugar can be used for energy. This insulin surge tells our body that plenty of energy is readily available and that it should stop burning fat and start storing it.

However, the greater concern with the insulin surge is not that it tells our body to start storing fat. Another side effect is that the insulin surge causes too much blood sugar to be transported out of our blood and this results in blood sugar and insulin levels to drop making us feel tired and hungry. This  makes us crave to eat again, preferably something with a high sugar content. Your body gets into a constant state of storing fat.

Sugar mostly resides in simple carbs. Simple carbs include the various forms of sugar, such as sucrose (table sugar), fructose (fruit sugar), lactose (dairy sugar), and glucose (blood sugar). Watch for the “-ose” ending. Derivatives like High Fructose Corn Syrup (HFCS) and Corn Syrup also fall in this category.

Most everything has sugar that is why I believe in keeping it to a minimum because of the insulin spikes it creates. I even frown on eating lots of fruits since those are high in sugar. Some may be critical of that but the fact is, sugar is sugar is sugar regardless of the source it has the same effects on insulin.  If you eat fruits for the fiber content, convert some of that consumption to high fiber vegetables. Overall it is better than gouging on fruits all day long.

Again, the key is lowering your sugar content. Eating a fruit before a work out is ok but don’t eat it all day because of the fiber content. It makes no sense, you are ingesting unnecessary sugar when you can get your fiber content somewhere else.

Caution: Sugar, sugar everywhere…

It is very hard to keep sugar consumption to low levels since it is everywhere and in foods that most people do not consider as a sugar source. For example:

  • Milk; regardless of type, skim, whole, 1% or 2%, almond, soy, organic, etc, etc, loaded with sugar
  • Breakfast cereals; almost all of them are loaded with sugar
  • Soft drinks; probably the worse of all in terms of sugar content
  • Canned or Frozen food; pumped with sugar and its derivatives in order to preserve shelf life which minimizes spoilage at the store before someone purchases it
  • Low to No Fat Products; usually compensated by adding sugar for taste. I prefer ‘low’ versus ‘no fat’ products. I will trade fat grams over sugar grams any day of the week
  • BBQ sauces; most all are high to super high in sugar. I prefer to use rubs on my fish, chicken and meat. I trade in sodium content over sugar any day of the week
  • Ketchup and Salad dressings; read the labels, get the ones with the lowest sugar content. I strive for something under 3 grams of sugar per serving. This has a nice trade off and balance with fat grams


When setting up your Protein, Carb and Fat macros, you should further break down your carb intake to simple and complex carbs which equates to controlling your sugar intake and maximizing your fiber intake.

Even if you do not do anything else in your diet plan except to decrease sugar consumption and increase fiber intake, you will see results in terms of weight loss.  I have seen that in every client I have ever trained.

Cut out sugar and add fiber in order to become….Fit Forlife

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