Difference between refined and unrefined carbs

Difference between refined and unrefined carbohydrates

Pawel Malczewski
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Short Summary

The definition of refined carbohydrate foods refers to two highly processed food groups: refined sugars and refined cereals.

Refined sugars are simple sugars (fructose, glucose and sucrose) extracted from plants (e.g. sugar cane, sucrose from beets, fructose and glucose extract from agave plant and fruit and vegetable juices). Refined cereals are cereal foods with bran and germ partly or fully removed during the processing, leaving mostly starch.

Unrefined carbohydrates refer to any starchy tubers, fruit, legumes, and whole cereals. For a quick answer click here.

EXPLANATION

Refined vs unrefined carbohydrates

In the nutritional sense, it is more useful refer to carbohydrates as refined or unrefined rather than simple or complex. (read more..)

The distinction between refined carbohydrates and unrefined (or as some people call “whole”) carbohydrates is more relevant considering the effects that foods exert on us.

The definition of refined carbohydrates is synonymous with “bad carbs”. Unrefined carbohydrates, although, in general, healthier, include some carbohydrates that, depending on the quantity consumed, also belong to the “bad carbs” group.

Refined carbohydrates

The refined carbohydrates definition refers to foods that have undergone heavy processing with the goal of deliberately removing fiber (e.g. brown rice stripped of the fiber = white rice), changing the foods natural composition.

Refined carbohydrates foods include:

  • table sugar (white or brown);
  • sugar based soft drinks (sodas);
  • syrups (e.g. agave, HFCS or maple syrup);
  • stripped of fiber fruit juices, and;
  • starchy foods produced from refined cereals, such as white bread, white rice and white pasta.

There are, however, some misconceptions about what is considered refined carbohydrates:

Note 1: Not all processed carbohydrate foods are refined carbohydrates.

Some sources considered highly processed foods, such as French fries or dried fruit, as refined carbohydrates, since they have undergone processing and are considered unhealthy (e.g. they cause the rise of blood glucose levels).

However, these are still unrefined foods since they have not been purposely stripped of any nutrients, and fiber was not removed. French fries for instance are simply potato pieces or thin slices that, although deep-fried in high temperatures, don’t change their original composition. In the process, some nutrients and antioxidants are lost, but not as much as through other forms of cooking. (1)Fillion L, Henry CJ. Nutrient losses and gains during frying: a review. Int J Food Sci Nutr. 1998 Mar;49(2):157-68. Available here. Dry fruit are devoid of water, and some preservatives are added for longer shelf-life. Nevertheless, they still retain most of their original nutrients.

To keep the definition of refined carbohydrates clear and consistent, it makes sense to separate foods which have been deliberately devoid of nutrients to create another product, from foods that have lost some nutrients due to processing, such as cooking and keeping the core of its original composition. It would be difficult otherwise to draw the line of how much processing turns the food into refined food.

Note 2: Not all refined carbs are simple sugars.

You might have heard some references to white bread as “simple sugar” or “simple carbohydrate” food. To be precise, white bread, pasta or rice, are complex carbohydrates in the biochemical sense, since they contain starches built of hundreds and thousands of glucose units. (read more..). They are also included in the refined carbohydrates group, since they are stripped of fiber (the fiber added to the final product doesn’t change that fact). (2)Smolin LA. Nutrition: Science and Applications. 3rd Edition. Wiley. Available here.
“Refined carbohydrates” are commonly, but incorrectly, called “Simple carbs”. Simple carbohydrate refers to a chemical definition describing 1-2 carbohydrate units, which includes unrefined products such as honey. Honey can be collected from bee hives and eaten without going through any processing, yet it contains only simple carbohydrates/sugars.

Therefore, “simple sugar” or “simple carbs” doesn’t imply “refined carbs”.

Unrefined carbohydrates

The unrefined or “whole” carbohydrates refer to carbohydrate containing foods that have not been stripped of fiber through processing.

This group includes whole vegetables, such as tubers, fruit, legumes and whole cereals, all of which come naturally with fiber. Pure unrefined honey, although it contains no starch, but simple sugars, also belongs to this group since it hasn’t been refined or processed.

Unrefined carbohydrates are generally healthier than refined carbohydrates, although it is highly dependent on the quantity consumed and the quality of these foods. For instance, a standard serving of boiled potatoes (unrefined) may raise blood sugar levels more than a standard serving of table sugar (refined). (read more..)

Nevertheless, there is a misconception regarding unrefined carbohydrates. It is when they are incorrectly referred to as “complex carbohydrates”. Complex carbohydrates is a very general term which has no use in nutrition (read more..).

Although all unrefined carbohydrates are complex in the biochemical sense, some complex carbohydrates are refined (e.g. white rice, white bread and white flour pasta).

Conclusion

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Think of refined carbs as those plant foods with the fiber removed and with a high concentration of carbohydrates, such as simple sugars or starch products.

Unrefined carbs, although they could have undergone processing, such as cooking, retain their natural fiber contents, with honey being an exception, since it is unrefined and has only simple sugars.

Bear in mind that “unrefined carbs” doesn’t necessarily mean “good” carbs.

References   [ + ]

1. Fillion L, Henry CJ. Nutrient losses and gains during frying: a review. Int J Food Sci Nutr. 1998 Mar;49(2):157-68. Available here.
2. Smolin LA. Nutrition: Science and Applications. 3rd Edition. Wiley. Available here.