Making Sense Of Science: The Truth About Carbs - Part 2

By Krista Rompolski, PhD

In the first article in this series, I presented some basics on what carbohydrates are, the various types of carbohydrates in our diet, and how our bodies use carbohydrates for energy. This is, of course, probably not why you’re reading.

If you are like most people, you are interested in weight loss, weight maintenance, body composition, or performance. You are reading to know how many carbs you need, what kinds you need, or you simply want to stop fearing carbohydrates.

If you are afraid of carbs, who could blame you? The food industry both glorifies and demonizes carbohydrates.

The weight loss industry has been a driving force against carbohydrates since the early 90s, when the Atkins Diet emerged. Taking a brief walk through fitness/dieting history, you will see that fat was once the root of all food evil, and sugar was either no problem or was actually presented as a health food!


You may laugh at the absurdity of those ads, but is today’s situation any less ridiculous or confusing? Brands seem to be having an identify crisis.


That said, we aren’t here to discuss marketing or food lobby motivations, only to understand how carbs got such a bad rap. It used to be that there was a small section of a grocery store dedicated to low sugar and low carb products, and the only patrons were diabetics.

You could argue that they are simply giving consumers options, but their profit is driven by our utter confusion about the right choices for us.

Not surprisingly, the history of low-fat diets and low-carb diets are strikingly similar. Studies conducted during the 1940s–1980s showed correlations between high-fat diets and high-cholesterol levels, and found that reducing fat in the diet could lead to weight loss and subsequently, lower cholesterol.

This shouldn’t surprise us — fat has more than twice as many calories of energy per gram as carbohydrates and protein. Thus, if you were cutting back on oil, butter, and animal products and substituting spices and leaner meats, total calories would be reduced.

However, the industry made a mess of things. To keep products selling and respond to the new generation of dieters, many snack food companies began to sell reduced fat versions of their foods. However, if you remove fat, you remove flavor. So how did they keep products selling?

Sugar. Almost every reduced-fat or fat-free product (that in its original form is neither low-fat or fat-free) has added sugars. The result was products almost identical in total calories.


Regular Oreos: 160 cals/serving; reduced fat Oreos: 150 cals/serving


Having these new products, but little to no knowledge of calorie control, consumers started gobbling up the added sugars, and this also coincided with a boom in diabetes rates. Researchers turned their attention off of fat and onto carbohydrates and found that reducing carbohydrates, particularly simple carbohydrates, improved blood glucose and insulin levels. Since regular intake of high carbohydrates leads to continuous increases in blood sugar and a greater demand for insulin, reducing simple carbohydrate intake places less stress on a tired pancreas and improves blood glucose control. Chronically elevated blood glucose levels causes a wide range of problems for the body, including vascular disease, vision complications, kidney disease, skin conditions and nerve damage. Yikes!

On the heels of diabetes research, the 90s brought the birth of low-carb diets, most notably being The Atkins Diet. The Atkins plan was quite successful for many people – simply restricting carbohydrates seemed to be melting the pounds away. Many other popular diets followed including the Zone and South Beach, which were less restrictive on carbohydrate intake but still focused on avoidance of food groups rather than calorie counting.

People reported feeling more in more control of their cravings, desiring less volume of a given food, and less mindless eating. Again, not surprising. What do you see people overindulging on more frequently, carbohydrates, or protein and fat? It has been suggested that sugar is addictive, eliciting similar responses in the brain as a number of drugs.

Our brains light up like a Christmas tree when we consume high sugar foods, with some people experiencing greater responses than others based on genetic variation and/or conditioning.

From a biological and survival standpoint, this is was intended to be a good thing! It is a primitive mechanism that helped our ancestors know that a food was not poisonous and contained an abundance of energy. The cavemen weren’t concerned about their body fat. Body fat meant stored energy to keep on living. However, our brains and genes didn’t quite catch up to today’s "drive-thru" culture.

Research over the past 20 years has been mixed on the effectiveness of low carb, low-calorie and low-fat diets for weight loss and maintenance of weight loss. Most studies have found no significant difference in weight loss whether people are assigned to low-fat or low-carbohydrate diet, as long as calories are the same between groups.

From a practical standpoint, however, since low-carb diets do not prescribe calorie-counting, studies needed to be conducted comparing low calorie diets with diets restricting carbohydrates but without calorie limits. Several studies of this model found that the low-carbohydrate diet produced greater weight and fat losses at six months, but found no difference between the groups at 12 months.

Why would this be?

The best explanation from researchers has been from participant feedback indicating that they experienced greater satiety levels and less mindless eating. A higher protein diet typically creates higher satiety levels and thus, potentially less calories consumed. A number of these studies also found improvements in blood glucose control, insulin resistance, and surprisingly, blood cholesterol and triglyceride levels in the low carbohydrate groups.

It seems that whether assigned a caloric level, or told to restrict carbohydrates, participants who end up in an energy deficit lose weight. There is no overwhelming evidence for one type of dietary approach over another, but this indicates that simply being consistent with some type of food intake monitoring does the trick.

So what about increasing obesity rates worldwide?

The increase in obesity rates around the world is a result of several contributory factors, not simply an increased intake in added sugars. We can argue a number of other influences: increased stress, less sleep, less time to cook, abundance of food available everywhere in the environment, less physical activity, you name it – it is almost too easy to gain weight and lose health.

Technically speaking, carbohydrates are not an essential nutrient, since our bodies can covert protein to glucose and fats to ketones, as we mentioned in the previous post.

However, there is a large difference between surviving (i.e. just getting the essentials) and thriving (i.e. having optimal health). The earth is abundant with carbohydrates!

carbs-450x279Carbohydrates provide a variety of vitamins, minerals, and dietary fiber, they stimulate serotonin release, and they are readily available at a low cost. Thus, if you are leading an active lifestyle, avoidance of carbohydrates can be detrimental to health, and low glycogen stores will limit performance, particularly in any sort of endurance activities. Our bodies are designed to survive, but carbohydrates can help them thrive.

Even body builders who typically follow a diet low in carbohydrates understand the metabolic benefit of a few “cheat days" of high carbohydrate intake. They seem to signal to the brain, “all is well.” Just as too much simple carbohydrate intake can lead to excess blood glucose levels and the problems associated, too few can lead to hormone deficiencies and mood disturbances, particularly in women.

And THAT is enough of the boring science stuff. Check out Part 3, where I discuss how to apply this information to yourself!

Are you tired of trying every diet plan and exercise program under the sun?

Sign up for this FREE 5-Day course and you'll learn how to:

  • Ditch dieting for good and still get amazing results
  • Exercise less and feel better than ever before
  • Know exactly what to do in the gym (and what not to do)
  • Stay consistent even if you're busy, injured, or unmotivated
  • Learn simple, but important strategies for making your results last
Get started today

Step Off the Diet and Exercise Roller Coaster Forever

It’s time to get the best results of your life — without feeling deprived of the foods you love — or exhausting yourself with exercise.

This free course includes videos, downloadable tools & resources, and podcast version so you can learn on the go.

About the author:  Krista Rompolski, PhD

Krista Rompolski, Ph.D.: Krista holds a doctoral degree in exercise physiology from the University of Pittsburgh and is a certified exercise physiologist through the American College of Sports Medicine. She is an assistant professor at Drexel University, where she teaches anatomy and physiology, pathophysiology, exercise physiology and courses in clinical research. In addition to conducting research and writing several articles for Girls Gone Strong, Dr. Rompolski is the Lead Digital Author and new contributing author for Fox's Human Physiology, 15th edition, a McGraw Hill publication. Furthermore, Dr. Rompolski wrote a chapter on exercise recommendations for obese pregnant women in Pregnancy in the Obese Woman: Clinical Management in 2012. Krista is passionate about body positivity and removing weight bias and weight stigma from our culture. To contact Krista, connect with her on Twitter.

More Resources

envelope-oclosechevron-upchevron-downbookmark-otwitterfacebookchainbars linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram