by: Le'Vena Tan, Nutrition Masters Student & Guest Post Writer
From sugar taxes, listing added sugar on nutrition labels, to words like ‘’toxic”, ''poison”, ''evil” constantly being used to describe sugar, sugar gets a lot of bad press from public health professionals and the media as being the food to avoid. Recently, I saw a social media post about dietitians being advocates for carbohydrates/sugar, because of misconception and fear surrounding sugar propagated by diet culture.
What is sugar and why is it important?
Sugars are broken down forms of carbohydrates. They supply our body with energy necessary to perform our day-to-day activities, resting, eating, thinking, moving etc. Sugar is a great quick source of energy to help restore our blood sugar, especially when it is low. An added bonus, sugar tastes good! There are three different types of sugars: simple sugars (monosaccharides), disaccharides (containing 2 sugar molecules) and complex sugars (polysaccharides).
The science behind sugar metabolism
Glucose is the simplest form of carbohydrate and the preferred form of energy for most cells in our body, especially the brain. After being absorbed into the body via the intestinal lining, glucose is broken down by the cells in our body to provide energy for essential metabolic processes and our daily activities. In excess, glucose is stored as glycogen, the storage form of glucose, or as fat in our body.
Fructose and Sucrose
Fructose and sucrose are found naturally in fruits, vegetables, and nuts. Fun fact: table/granulated sugar are examples of sucrose, manufactured from sugar beets or sugar cane. Fructose is a simple sugar just like glucose with a different chemical structure. Sucrose consists of equal parts glucose and fructose. The body has to break down sucrose into glucose and fructose molecules in order to use it for energy. It’s important to note that most sugars are typically consumed with fiber, vitamins, minerals, antioxidants and phytochemicals, which helps our body fight against diseases.
High Fructose Corn Syrup
High Fructose Corn Syrup (HFCS) is typically found in packaged foods and beverages. It is commonly 55% fructose and 45% glucose in beverages and 42% fructose and 58% glucose in baked goods and other foods. Similar to sucrose, HFCS needs to be broken down into its glucose and fructose molecules.
Our body processes sugar the same way, regardless of its source (naturally occurring or from manufactured, processed foods). But, there are some differences in the metabolic pathways glucose and fructose undergo in our body, even though the end-product of both are basically the same.
How do our bodies break down fructose?
- First, fructose is mainly broken down in the liver.
- Second, fructose has to undergo additional steps before entering the same metabolic pathway as glucose to provide energy to the body.
- Third, unlike glucose, fructose doesn't trigger insulin secretion, whose role is to regulate our blood sugar and hunger and fullness cues. Fructose intake can affect our hunger and fullness cues by increasing our desire and appetite for food and decreasing the satiety signal of our brain 1,2.
A word of caution:
it is helpful to know the science behind how sugars are metabolised in our body. But, it is even more important to note that we do not consume sugar in isolation and our diets typically consist of a variety of foods. The mechanisms of how food is broken down in our body is highly complex and hinges on many factors. For example, eating an apple with peanut butter (adding protein and fat), our body processes the fruit sugar differently than eating an apple alone. More reasons to not agonize over our sugar consumption.
What does this all mean?
I think this means that we shouldn’t go around labeling some sugars as good or bad. It doesn’t serve us to make rules about which sugars are better to avoid or worry about how much glucose or fructose we are taking in, or avoid sugar all together. These actions have the effect of making sugar all the more desirable, which contradicts the initial motivation in the first place. Black and white rules make us feel guilt and shame about our eating, which doesn’t lead to increased health and well being.
Instead of Using Rules
If sugar isn’t all bad, then how can we think about sugar?
Remember that everybody's biology, genetic make-up and history with food is different, so you can have very different reactions to different types of sugar to your friends or family.
Instead of thinking about food in a dichotomous, (good or bad) way, you can decide how sugar fits into your food intake. Trust your body. It has a lot of wisdom - and internal information is just as important as the external information we get from science, if not more so. Explore how your body and mind feel when you eat different sugar-containing foods.
- How does this (sugar-containing) food taste on my tongue?
- Does it taste good? Or is it just the idea of it that tastes good?
- How do I feel (physically and emotionally) immediately or a few hours after consuming it?
- Do I feel differently if I eat it with other foods?
- Am I hungry to eat this or do I want it because I usually don't allow myself to eat it?
Giving yourself the opportunity to explore how you feel after eating sugars, helps you understand your response to them and, maybe, get more satisfaction out of your eating experience. Being curious, rather than using rules, helps us eliminate the guilt and shame that can come from black and white rules. Tuning in, may help you identify the sugar-containing foods that you love and maybe others that you don’t really enjoy at all.
Le’Vena Tan is a graduate student in the Department of Nutrition at University of North Carolina at Chapel Hill. She is also a lactation student in the Mary Rose Tully Training Initiative (MRT-TI) under the Carolina Global Breastfeeding Institute. Her interests include pediatric and maternal nutrition, breastfeeding, responsive feeding, intuitive eating, Health at Every Size® and public health, especially food insecurity. She hopes to practice from a weight-inclusive lens and to utilize her knowledge in public health to help better the community. She enjoys engaging in creative pursuits and would like to incorporate some creativity in her work in the future. Le’Vena can be contacted via email at firstname.lastname@example.org.
- Lowette, K., Roosen, L., Tack, J., & Vanden Berghe, P. (2015). Effects of high-fructose diets on central appetite signaling and cognitive function. Frontiers in nutrition, 2, 5.
- Luo, S., Monterosso, J. R., Sarpelleh, K., & Page, K. A. (2015). Differential effects of fructose versus glucose on brain and appetitive responses to food cues and decisions for food rewards. Proceedings of the National Academy of Sciences, 112(20), 6509-6514.