Remember when fat was bad news in the 1990’s? Instead, we piled on more starches (or complex carbohydrates) on our plates. Now, carbs are bad and the trending issue is to avoid them at all costs. It seems the nutritional pendulum has swung far from those fat-free days in the 90’s to the carb-free days of today. But, what is the real story behind carbs?

Nutrition 101

It starts with a little nutrition 101: complex carbohydrates (aka starches) are made of hundreds (or thousands) of units called monosaccharides. In nutrition-ese when all these units are strung together, we call it a polysaccharide. These are essentially your starchy foods or grains, like bread, pasta, oats, and potatoes. (To be clear, simple carbohydrates are a whole other kettle of fish {that we won’t be covering here} and are found in high amounts in fruit, jam, candy, cookies & cakes).

Going back to the carb-heavy years in the 90’s and early 2000’s, the type of carbohydrates people consumed most was more refined starch – with much of the nutritional value depleted or eliminated. This was a problem. A big part of the nutritional value of starches is the fibre and its associated nutrients (usually B vitamins). When this was removed, as is the case with white bread, cakey muffins and many popular breakfast cereals, we tended to eat larger portions because there was so little fibre present to make us feel full or satiated.

 

Also, starchy foods are convenient and tasty– how easy is it to grab bread or a croissant to nosh? Or a bag of chips? Or grabbing a muffin in a drive-thru? Easy peasy, right? It takes a whole lot more work to cook up brown rice, quinoa or bake a sweet potato.

Next up is a little lesson in insulin – this powerful hormone, produced by our pancreas, is the body’s response to a surge of sugar in the bloodstream. I’m not just talking about sugar in your coffee or the cookies you ate after dinner last night. When starchy foods (& simple sugar foods) are broken down and digested by the body they break down to the simplest form of fuel – glucose (or sugar). This glucose is essential for your brain, muscles, etc. Without it, you may feel sluggish or have difficulty concentrating on tasks, for example.

It can be confusing, though, not knowing whether carbohydrates are the real enemy or not with the advent of seemingly credible sources highlighting the ills of starches. The internet, or Dr. Google, as I sometimes refer to the surfeit of online nutrition & medical information, can really muddy the waters of what is evidence-based and what is opinion. But, I am surprised every time I sit down with a patient who happily reports having given up bread, pasta and potatoes.

Let’s look at the evidence

Looking at the scientific evidence, we know with a high level of certainty that high fibre diets are important for decreasing risk for heart disease, obesity and diabetes (among other parameters like blood pressure, cholesterol, etc.). There are innumerable studies that have extolled the benefits as well as being a significant part of many national nutrition guidelines and recommendations for heart disease and diabetes.

When it comes down to it, the argument isn’t whether starch/carbs are good or bad, it’s rather, the TYPE of starch that matters. I went to the scientific literature to see whether the evidence had changed. I even found a study entitled ““Relationship between bread and obesity” from the British Journal of Nutrition! Could it get any plainer? Nope. So, what were their findings?

They looked at obesity and bread consumption in the context of a Mediterranean diet – something similar to the main tenets of Canada’s Food Guide. The Spanish study authors stated, “it appears that the different composition between whole-grain bread and white bread varies in its effect on body weight and abdominal fat”. This again highlights my point that high fibre, whole grain starch choices can (and do) make a difference in a healthy diet.

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In another interesting, though small study of overweight and obese females, researchers studied whether these women were more successful at losing weight when placed in a no bread diet group versus a group that allowed bread consumption. Interestingly, the no-bread group showed almost no differences in weight loss, waist measures and blood markers compared with the bread group. Also, they reported that the no-bread group was much less compliant with their diet regime by the 12-week mark, showing perhaps, that this elimination strategy was not a reasonable, long-term solution.

We can see that there’s no strong evidence to support eliminating starchy foods completely from your diet, even in individuals with diabetes. However, what does make a massive difference to your overall health is whether you’re piling on the refined starchy foods, like white bread, white pasta, white rice, and coffee shop muffins versus higher fibre foods. By cutting back on the lower fibre choices and pulling in more high fibre food choices into your day can make the difference in whether carbs are your friend in the end.

 sweet potato

Summary of some of the benefits of fibre:

  • Cholesterol lowering (particularly with soluble fibre-rich foods)
  • Reduction in obesity/weight management
  • Lower risk of diabetes
  • Lower risk of cardiovascular disease (including heart disease & stroke)
  • Lower blood pressure
  • Improves insulin sensitivity
  • Regularity with bowel movements
  • Better management of GI conditions (reflux, diverticulitis, hemorrhoids)

-Samantha
Sources:

Anderson, J., Baird, P., Davis Jr, R., Ferreri, S., Knudtson, M., Koraym, A.,Waters, V. and Williams, C. (2009). Health benefits of dietary fiber. Nutrition Reviews. 67(4):188–205. http://www.ncbi.nlm.nih.gov/pubmed/19335713

Loria-Kohena, V., Gómez-Candelaa, C., Fernández-Fernándeza, C., Pérez-Torresa, A., García-Puigb, J., & Bermejo, L. (2011). Evaluation of the usefulness of a low-calorie diet with or without bread in the treatment of overweight/obesity. Clinical Nutrition. 31(4):455-61. http://www.ncbi.nlm.nih.gov/pubmed/22209501

Satija, A. & Hu, F. (2012). Cardiovascular Benefits of Dietary Fiber. Curr Atheroscler Rep. 14:505–514. http://www.ncbi.nlm.nih.gov/pubmed/22872372

Serra-Majem, L. & Bautista-Castan ̃o, I. (2015). Relationship between bread and obesity. British Journal of Nutrition. 113, S29–S35. http://www.ncbi.nlm.nih.gov/pubmed/26148919

Photo sources: Foodphoto.ca