Science of Food: Simplifying sugars, the good and the bad |

Science of Food: Simplifying sugars, the good and the bad

Seek out honey, maple syrup and sugars that come in natural sources such as fruits and vegetables. All sugar must be eaten in moderation and consumed mindfully so as not to create glucose spikes.
Yelena Panyukova / Courtesy of ThinkStock Photos | Hemera

If you go

What: Simplifying Sugars, a perspective on the fundamental biochemistry of natural and artificial sweeteners, with Lisa Julian, Ph.D.

When: 2:30-4 p.m. Saturday, Aug. 8

Where: Elevated Yoga & Holistic Health, 310 E. Main St., Frisco

Cost: $20 per person, reservations required

More information: Visit

Sugars come in many forms, though on a molecular level, they contain only three atoms: carbon, oxygen and hydrogen. Carbohydrate is another word for sugar. The simple sugars are glucose, fructose and galactose and are the fundamental building blocks of many other types of carbohydrates. Glucose is what we measure as “blood sugar” and is an essential energy source for all the body’s activities.

From the simple single-celled organism to the beautiful and complex human being, we need sugar! Simple glucose and its polymerized form glycogen (which we cleverly store in the body as an energy reserve) provide about half of all the energy the muscles and tissues use. The other half of the body’s energy comes mostly from fat.

How sugars form

Nature links up single sugar molecules into sucrose (table sugar) or lactose (milk sugar), which are combinations of glucose bound to either a fructose molecule or a galactose molecule (see figure). It also strings them together into large chains, which we call complex carbohydrates or starches — found in potatoes, rice, corn and grains — that can contain thousands of molecules bound together, similar to how we store our glucose as glycogen, for reserve energy. When you eat sugars that are bound together like this, the body will metabolize or break the chemical bond linking the individual sugar molecules together, eventually leading back to the simple sugars, which we use for energy.

Sometimes the body has problems metabolizing sugars. For example, some people who are lactose intolerant cannot break the chemical bond between glucose and galactose. The enzyme responsible for this job is called lactase. I myself am lactose intolerant, however I still enjoy plenty of cheese! I just stick to mostly aged cheeses that no longer contain any lactose, as the natural aging process breaks it down after about six months. I encourage those of you who believe you are lactose intolerant to experiment for yourself.

Simple sugars are rapidly absorbed and released into the blood stream and good to eat for immediate energy use. On the other hand, complex carbohydrates or starches that contain more chemical bonds will take longer and more energy to break down (digest or metabolize). They will stay in the digestive tract longer and serve as a good source of reserve energy as glucose is released more slowly into circulation.

Interestingly, plants link up glucose in a slightly different way to form their strong structures (e.g. cellulose) or what we call fiber, and because of this structural difference, plant fiber does not actually break down in our bodies and adds no free glucose into circulation, unlike starches. All plants have fiber, and the physical properties of fiber make it essential to our gastrointestinal health, aiding in movement of food through the gastrointestinal tract and acting as a food source for the bacteria in our guts that promote a healthy gut flora. Fiber also slows the absorption of simple sugars when the two are eaten together in the form of whole fruits and vegetables.

Demonizing sugar

So why is sugar thought to be so bad? In Western cultures, we simply eat too much and the wrong kind. Based on all our current understanding of how glucose works in the body, it becomes strikingly apparent that our Western society’s issue with sugar comes down to large, concentrated doses, along with a sedentary lifestyle without a need for all that fuel, leading to glucose spikes in the body. In addition, sugary products are often not paired with any fiber or nutrients, so-called “empty calories,” making spikes even higher. Glucose spikes are like revving an engine, it takes a toll over time and wears it out faster, and in our bodies, it specifically wears out the response and sensitivity to insulin.

When the body absorbs glucose, it requires the small protein hormone insulin in about equal amounts to uptake the glucose into cells or store it in the liver as glycogen. When the body experiences repeated high glucose spikes, especially when consuming sodas and most processed foods, it becomes insulin resistant over time, unable to produce the required amount of insulin to match the high glucose spikes, which leads to metabolic disorders including obesity and type II diabetes. Furthermore, if the body isn’t using the sugar, more and more becomes stored and eventually forms visceral fat around the belly region, commonly seen in Western societies.

High-sugar diets in children are also being linked to childhood mental disorders such as attention deficit hyperactivity disorder and other learning and behavioral issues. Soda, candy and white bread are main sources of high sugar and empty calories. Too much sugar is also known to drive cancer progression because it drives cell growth.

The Bad: What to avoid

Avoid high doses, artificial sweeteners, “food products” with added sugars and “empty calories.” High-fructose corn syrup (HFCS) is by no means a natural source of sugar. It contains glucose and fructose, similar to table sugar, but the two molecules are not linked by a chemical bond and, as the name suggests, typically contains more fructose than glucose.

Fructose in nature serves as a signal for nutritionally rich foods such as apples and figs and is only present in relatively small amounts (less than 10 percent). Humans have never consumed so much pure fructose in their diets, especially without fiber and nutrients to go along with it. We now know that fructose behaves much differently than glucose in the body and high fructose consumption can lead to type II diabetes, fatty liver disease and even cardiovascular disease.

Avoid artificial sweeteners in general, including aspartame and Splenda (or sucralose so cleverly named to sound like the natural sugar sucrose). From my experience in the pharmaceutical industry studying the effects of manmade molecules in the body, I now prefer not to put any synthetic molecules in my body if at all possible. All molecules that enter the body have the potential to interact with the various proteins or receptors to turn on or off function; this is the basis of how drugs work. Splenda is especially suspect, in my opinion, as it contains notorious organochlorine bonds, not unlike those found in the highly toxic DDT. We now have an understanding of how chlorinated organic molecules metabolize in the body into potentially harmful free-radical intermediates.

In addition to potential toxicity, many artificial sweeteners often do not provide any source of calories, the highly praised “zero-calorie” sweeteners. Although these sugar substitutes do not raise blood sugar (the reason many diabetics have been advised to use them) many scientists believe over time this repeated activation of the sweet receptors on the tongue and transport mechanisms in the body, without actually receiving any glucose and other nutrients, leaves the body highly confused. It’s fooling with our innate glucose response system and may actually contribute to further insulin resistance.

The Good: What to eat

Seek out honey, maple syrup and sugars that come in natural sources such as fruits and vegetables. All sugar must be eaten in moderation and consumed mindfully so as not to create glucose spikes. Fruits package their simple sugars with fiber, vitamins and minerals, making them a delicious and healthy snack. Agave and Stevia are also “natural” sweeteners, as they do come from plants, but I avoid these since there is some speculation based purely on their chemical structures. Be mindful of anything that is taken daily and especially in higher doses.

Avoid “food products,” including sweetened yogurts and fruit juices, as they are a hidden source of sugar. Switch your habits and try eating an orange instead of drinking a glass of orange juice. Even table sugar is not bad, again when eaten in moderation and paired with nutrients. It is the fast rate of absorption of sugars into the blood stream that creates the glucose spikes and revs the engine of your insulin system. So I began baking my own cookies and brownies at home to control the amount of sugar and to experiment with adding various nutritious nuts, seeds and dried fruits — I even make cookies with fresh turmeric root.

We must also focus on energy balance and matching energy input with energy output to support healthy cellular function and a healthy body. The high dose of sugar found in processed foods is a major cause of the epidemic in type II diabetes and obesity in this country. Eat sugars when your body is ready to use them, not on a day behind the computer. Watch less television after a meal, and go for a walk.

We have evolved with a reward mechanism in our brain that exists when we find sugar; it is the evolutionary basis for our “sweet tooth,” and it is not wrong to enjoy nature’s gifts of honey and fresh summer berries, perhaps served with some cool homemade whipped cream. Our cells and our bodies need it to survive. The key will be finding the balance for our own unique bodies: Allow nature to be your guide.

Lisa Julian, Ph.D., has a passion for organic chemistry — the “molecules of life” — and its application to food and health. She’s the owner of Elevated Yoga & Holistic Health in Frisco and teaches science and nutrition at the University of Colorado Denver and Colorado Mountain College. She can be reached at or (970) 401-2071. For more information about services offered at her studio, visit

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