Dr. Mitchell Weisberg
I originally published this post two years ago but I decided to re-post it in response to a new “weight-loss” product gaining popularity called, Sensa.
It just can’t be true! How can a mere 12% increase in our daily caloric intake can result in a three-fold (300%) increase in the childhood obesity rate in just a single generation? According to statistics from The United States Department of Agriculture (USDA) this is precisely what occurred in the United States between the years of 1980 thru 2004. While I am not one to rely on damn statistics, in this particular instance, the stats quite literally add up, and they point squarely at the root cause of the world-wide Obesity Epidemic;
IT’S THE FIBER, STUPID!
This 12% translates into each American eating an additional 300 calories per day, 138 of which are coming from refined grains. Understanding how such a seemingly minute amount of refined grains can have such an exponential impact on our national Body Mass demands a review of some of the basics of cellular metabolism. Based upon its proportions of Carbon, Hydrogen and Oxygen atoms, dietary fiber is classified as a carbohydrate. Unlike other carbohydrates, such as sucrose (table sugar), fructose (fruit sugar) and lactose (milk sugar) which contain 4 calories per gram, there is no enzyme in the inner lining of the human digestive tract that allows fiber into the bloodstream where cellular metabolism takes place. Therefore, in reality, fiber has no calories.
By remaining within the digestive tract, fiber enhances satiety (the sense of being full or satisfied) and effectively reduces the total amount of food an individual consumes. Moreover, fiber reduces the rate at which other nutrients (carbohydrates, fats and proteins) ingested together with it are absorbed into the blood stream. This in turn facilitates a more complete extraction of the energy in the food that we eat by our 40 trillion cells, the actual site of cellular metabolism and reduces the amount of energy left over that would be stored in our bodies as fat. In other words, the physical and chemical properties that cause fiber itself not be metabolized are the same properties that allow dietary fiber to optimize the process of cellular metabolism. It is these same properties that underlies the abundant evidence that a generous intake of dietary fiber reduces risk for developing the following diseases: coronary heart disease,1 stroke,2 hypertension,3 diabetes,4 obesity,5 and certain gastrointestinal disorders.6 Furthermore, increased consumption of dietary fiber improves serum lipid (cholesterol) concentrations,7 lowers blood pressure,8 improves blood sugar control in diabetes,9promotes regularity,10 aids in weight loss,11 and appears to improve immune function. However, average fiber intakes for US children and adults are less than half of the recommended levels.
Always the optimist, I see the silver lining in the USDA’s statistics. Rather than our collective obsession over what not to eat, we can turn our attention to a much more positive and practical message about what it is that we should eat. To illustrate the rationale for this paradigm shift, I will naturally offer you some food for thought. Imagine that we eat a slice of chocolate cake and then test ourselves for the glycemic index of this piece of cake. The technical explanation of the glycemic index of food is the area under the two-hour blood glucose response curve (AUC) following its ingestion. Simply stated, the glycemic index measures how much of the energy from the piece of cake will be turned into actual energy available for our bodies to use versus how much of the energy from the piece of cake will go un-utilized and stored in our bodies in the form of fat. Now imagine we eat a second piece of chocolate cake identical to the first one but, the only difference being that to this piece of chocolate cake, 3 grams of fiber is added to the recipe. The glycemic index after eating this piece of cake will be be significantly lower than the first piece. In other words, the addition of a relatively small amount of dietary fiber allows us to get more useable energy and store less of the energy as fat from, an otherwise identical piece of chocolate cake.
Processing food breaks down whole grains and causes a classic double whammy. First, the refinement of whole grains removes the two major benefits of fiber I just stated; enhanced satiety and metabolic optimization. Secondly, once whole grains are refined they become the metabolic equivalent of pure sugar. Now when we ingest processed grains they are completely and almost immediately absorbed from our digestive tract into our blood stream and flooding our 40 trillion cells all at once. This does not allow our cells to be efficient in extracting usable energy which explains why diets high in processed sugar leads to Obesity. Ironically, Obesity is a sign of cellular starvation!
When viewed from the perspective of cellular metabolism, we can see that it is no coincidence that in the same 25 year period that we added an extra 138 calories per day of refined grains to our diets that our nations childhood obesity rate tripled. The lesson we need to be passing on to our children now becomes equally clear; let them eat cake and their fiber too!