Why too many carbohydrates are bad for diabetics

20 Nov

When a patient is first diagnosed with diabetes, the first diet advice they usually get from their physician is “eliminate the white stuff”, referring to white flour and white sugar products. They’re also told to reduce the overall amount of carbohydrates in their diets, especially if they’re overweight or obese.

diabetes bad carbs good carbs

This is absolutely the right advice. However, there is a steep learning curve when newly diabetic patients have to understand which foods are classified as carbohydrates (it’s not just the fun stuff), which carbs are good vs bad, and why over consumption of refined carbohydrates might have led to their diabetes (but not necessarily-genes and a sedentary lifestyle may also factor).

What is a carbohydrate?

First of all, we need to understand what a carbohydrate is and what separates the bad from the good. For our purposes, a carbohydrate may be defined as the class of foods which include sugars, starches, and cellulose. They are further classified according to the kinds of sugars they contain. All carbohydrates (in their unprocessed form) are produced by green plants, and we consume carbohydrates to access energy (calories) faster than that supplied by fat and protein. Carbohydrates appear in simple form (sugars) and complex forms (starch and fiber), frequently together. In our bodies, most of these sugars and starches are broken down at different speeds to supply glucose, which is the primary sugar our cells utilize for energy. The energy produced by each gram of carbohydrate or protein is four calories. One gram of fat provides 9 calories.

Carbohydrates are essential for optimum health. The problem with the American diet and why too many carbohydrates are so risky for diabetics is in the second part of that definition – carbohydrates are synthesized into glucose (aka blood sugar) in our bodies. That is, ALL carbohydrates one way or another eventually end up as glucose and a handful of other nutrients. What makes one carbohydrate good and another bad is the speed at which we digest it (in simple terms), which is largely determined by the amount of refinement or processing it’s undergone. This is why “the white stuff” – heavily refined white flour and white sugar – should be the first carbs we seek to reduce in a diabetic diet.

Flour and sugar weren’t born bad, we made them that way
diabetes wheat good carbs bad carbs

The over refinement of wheat lead to many of our dietary problems

Flour is the product of seeds from the wheat plant, and as seeds, are highly indigestible. But when crushed or ground into dust, wheat seeds become flour and end up as bread, pasta, cakes, pie crusts, you name it. The first humans to discover this were using all of the parts of the crushed seed and receiving the excellent nutrition it contains. But with the invention of the first industrial mill in the 18th century, the wheat seed was separated into its constituent parts, and the outer shell (bran) stripped, which contains the fiber and unfortunately, the B vitamins (synthetic versions of which are added back in to white bread). The new refinement techniques were a revelation for chefs worldwide, as white flour could be utilized to make foods which were lighter, and easier to color, flavor and manipulate than their whole wheat counterparts.

But in the past 50 years (which coincidentally mirrors the rise in obesity and diabetes), the very nature of the wheat plant has changed as new strains with higher gluten and starch have been introduced into agriculture. When combined with the super refinement of modern milling techniques, these wheat products are like a bomb on our glucose levels. Similarly, sugar from sugarcane has also undergone super refinement in the past fifty years and like wheat, barely resembles the plant our ancestors knew. What does that mean in our bodies? It’s the difference between putting a dried-out twig on a fire or a log.

Our modern digestive tracts are nearly identical to our stone age ancestors. For all of the outward changes that evolution has wrought, internally, we’re much the same as we were. Our bodies run most efficiently on lean proteins and the fats they contain, and carbohydrates like raw or slightly cooked seeds, fruits, and vegetables. When these carbohydrates are eaten in their natural state, they break down slowly in our digestive tracts, supplying a consistent stream of glucose for our brains and bodies.

But the refined white sugar and white flour products we consume are an alien substance to our bodies, digesting too quickly and supplying too much glucose too quickly. The pancreas, which delivers insulin to control the glucose uptake in fat cells, skeletal muscles, and the liver, simply can’t keep up. Eventually, cells become resistant to the high levels of insulin, and therefore unable to take up glucose properly. This breakdown allows the excess sugar to float through your bloodstream where it upsets other functions as well. Welcome to Type 2 diabetes.

So which carbs are good and which are bad for diabetics?

When you are diagnosed with diabetes, you’ll have to become a label reader at the grocery store. There’s a stunning amount of added sugars and starches in nearly anything boxed, bagged, or canned, and many are disguised under a host of trade names. Do not trust the word “natural” on packaging, as the FDA has yet to create any standards for this label. Since wheat and sugar in all its forms can be interpreted as  natural products, any form may be included. And “wheat flour” on a bread label does not mean the same thing as “100% whole wheat” – it’s all wheat flour, whole or refined.

Generally speaking, good carbs are those that still have their fiber intact (like raw apples, raw carrots, brown rice, or black beans). The sugars and starches in these foods break down slowly, and their fiber, which passes through undigested, makes us feel full. Bad carbs are those which have been refined (white bread, white rice, crackers, cookies, white pasta). The bad carbs make us feel good for the same reason they may lead to diabetes: they spike blood sugar quickly. While this quick blood sugar infusion makes us feel emotionally satisfied, refined carbs don’t make us feel full because they lack fiber and protein.

It can all be quite confusing, but as a rule of thumb, the best advice is to avoid all processed foods (boxed, bagged, canned), and all restaurant fast foods. The simplest advice is found in Michael Pollan’s book “Food Rules, An Eater’s Manual”, in which he says, “Eat nothing that your grandmother wouldn’t recognize as food”, and “eat real food, not too much, mostly plants”.  Another good bit of advice is to eat no food handed to you through a window.

For more info, check out this great article on carbohydrates, insulin and diabetes from the Harvard School of Public Health and Health Gains From Whole Grains

Names of sugars which are added to foods

Names of starches added to foods

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