The Effect of Refined Carbohydrates on the Metabolism

Bread made with refined wheat flour can lower your meal-induced energy expenditure.


Metabolism is the sum total of the chemical reactions that occur in your body. Your total daily energy expenditure is determined by your metabolism at rest, also called basal metabolic rate, your metabolism increase due to the ingestion of food, also called the thermic effect of food, and your physical activity level. Consuming too many processed, refined carbohydrate foods can not only produce nutrient deficiencies, but it can also lead to the development of chronic metabolic diseases such as diabetes and heart disease. Furthermore, compared with whole, unprocessed carbohydrate foods, refined carbohydrate foods lower the thermic effect of your meals, cause you to gain weight and decrease your basal metabolic rate.

Refined Carbohydrates

Refined carbohydrates include sucrose, or table sugar, high fructose corn syrup and any foods containing these ingredients such as soda pop, processed syrups, jellies, preserves, pastries and desserts. The other major source of refined carbohydrates in your diet may be foods made with refined cereal grain flours. Compared to whole foods containing unrefined carbohydrates, refined carbohydrate foods tend to have a higher glycemic index, which is essentially the relative ability of a food to raise your blood glucose level. In this regard, regular consumption of refined carbohydrates will increase your risk for developing Type 2 diabetes.

Nutrient Loss

The refinement of wheat serves as an excellent example. Whole-grain wheat berries are milled to grind off the outer bran layers and germ to produce flour with a finer texture and extended shelf life. In this process, most of the fiber, essential fatty acids, vitamin E, B vitamins and essential minerals are removed. Countless other known and undiscovered phytonutrients are also lost. Although a few of the major B vitamins and iron are added back to the flour to produce enriched flour, the nutritional quality of refined wheat flour is inferior to that of whole-wheat flour.

Thermic Effect

The thermic effect of food, also called specific dynamic action or diet-induced thermogenesis accounts for about 10 percent of your daily total energy expenditure. Meals that are more complex, which require more work by your gastrointestinal tract and other digestive organs, greater enzyme production and more secondary metabolism in your liver have a higher energetic cost than less complex meals. Your energy expenditure due to a thermic effect after consuming a refined carbohydrate or processed food meal may be only about one-half of that after consuming a whole-food meal containing complex carbohydrates and dietary fiber.

Weight Gain

Excessive consumption of refined carbohydrates will tend to increase your fat mass, body weight and body mass index, or BMI, which is a measure of your fatness. Refined carbohydrate foods are rapidly digested and absorbed, and they tend to elevate your blood glucose level very quickly. This causes your pancreas to produce more insulin to prevent your blood glucose from getting too high, which sets up a scenario for your liver to secrete triglyceride-rich lipoproteins and subsequent triglyceride deposition in your fatty tissues. In turn, an increase in your fat mass will tend to lower your basal metabolic rate.

Want To Choose Whole Grains?

Good Luck!
Most of what you think are whole grains… are really not.  If you want to choose the right grains, look out for these ingredients:

Whole grain [name of grain]
Whole wheat
Whole [other grain]
Stoneground whole [grain]

Brown rice:  Oats, oatmeal (including oldfashioned oatmeal, instant oatmeal)

Wheatberries:  Yes, these are whole grains.

These COULD be whole grains… or not.

Wheat, or wheat flour Semolina
Durum wheat

Organic flour
Stoneground [grain]
Multigrain:  (may describe several whole grains or several refined grains, or a mix of both)

These are NEVER whole grains.

Enriched flour
Degerminated [grain]
[Grain] bran
Wheat germ