Now that science is showing dietary fats aren’t the primary cause of the obesity and metabolic disorder epidemics plaguing Western societies, dietary sugars are getting a closer look. It does appear over-consumption of sugar, added sugars in particular, are contributing factors to the increasing numbers of obese and individuals with Type II diabetes of recent decades. So, today we’re talking sugar.
What Is Sugar?
Sugar is the layman’s term for saccharides. Saccharides reside naturally in any food in our diet that contains carbohydrates. Therefore, virtually every food derived from plants – beans, nuts, fruits, vegetables, grains – contains some form of sugar. Dairy also contains natural sugars.
The simplest form of saccharides are monosaccharides of which there are three: glucose (aka dextrose), fructose and galactose. Many foods contain combinations of two monosaccharides, known as disaccharides. There are three types of disaccharides: sucrose in produce (glucose + fructose); maltose in grains (two glucose molecules); lactose in milk (galactose + glucose).
Do We Need Sugar?
Yes, we do need sugar. And, if you’ve ever experienced a bout of low blood sugar that led to light-headedness or fainting, you understand why.
All sugars in our diet are broken down by the digestive process into fructose and glucose and sent to the liver where they’re further processed into glycogen. Some is stored and some is released into the blood, known as blood glucose. Blood glucose is necessary to maintain cell function and to store in muscle as fuel for movement.
However, too much glucose in the blood can be toxic. In response to glycogen being produced in the liver, the pancreas releases the hormone insulin, which serves as the gatekeeper to blood glucose. Insulin is necessary to keep blood glucose from getting too high.
People who have Type II diabetes have insulin resistance and some are also inefficient at producing insulin. Unless they take lifestyle or drug interventions, their blood glucose will be chronically high. There are many theories as to why the number of adults and children developing diabetes has increased. One theory is the over-consumption of sugars, resulting in a rollercoaster ride of blood glucose and insulin production which could lead to dysfunction.
Diabetes isn’t the only threat from over-consumption of sugars. Unused carbohydrates get stored as body fat. Some body fat is vital. But an excess of it, especially visceral fat stored in the abdomen, is unhealthy.
As we’ve learned with fats and proteins, we need them to survive but too much, particularly of the wrong kind, can be detrimental to our health. The same is true of carbohydrates and the sugars they contain. What’s the right kind of sugar and how much is enough?
The quest to answer this question led scientists to develop The Glycemic Index (GI). The GI ranks foods on a scale from 0 to 100. The higher the number the food is assigned, the higher that particular food raises blood glucose levels after consumption.
Many assume fruits contain more sugars than vegetables and, while that’s generally true, it’s not always the case. Yes, lettuce’s GI is 10 and watermelon’s GI is 72. But cherries have a GI of 22 while pumpkin’s is 75. The problem with using generalities or a GI number to guide food choices is that it’s more complicated than that. For example, watermelon’s GI is seven points higher than granulated sugar. Even without taking into consideration that watermelon has vitamins, minerals and fiber and sugar doesn’t, no reasonable person would conclude it’s healthier to eat sugar over watermelon.
What we need to be careful about is added sugars – sweeteners added to pre-packaged and home prepared foods. Added sweeteners like granulated sugar, syrups and honey are predominantly sugar with little to no nutritional value. Too much of them in addition to the natural sugars we already consume in whole foods is how we’re likely getting into trouble.
Here’s an overview of common added sweeteners:
Raw Sugar: Most table sugar comes from either sugar cane or sugar beets. In both cases, the plant is heated into juice and put through a centrifuge. This separates the syrup from the sugar crystals. Molasses is a by-product of this process. These sugar crystals, called raw sugar, are brown, course and 97.5% sucrose. The remaining 2.5% is molasses which contains minerals and water. Turbinado sugar is raw sugar with the surface molasses washed off making it appear whiter.
White Granulated Sugar: White sugar (99.9% sucrose) is the result of refining raw sugar by removing the molasses and grinding into finer crystals. Simple (cane) syrup is made by dissolving granulated sugar in boiling water, forming a sweet liquid that incorporates better into cold drinks than grains of sugar.
Confectioner’s Sugar: Powdered sugar is white granulated sugar that’s milled to a powder for a lighter texture. An anti-caking agent, such as corn starch, is often added.
Brown Sugar: Brown sugar is granulated sugar with molasses added back in. Therefore, brown sugar has traces of minerals and water and is slightly less sweet than white sugar. Dark brown sugar has a higher molasses content compared to light brown sugar.
Invert Sugar: The product of the hydrolysis of sucrose into equal parts fructose and glucose. This occurs naturally in fruits and honey. Food manufacturers duplicate this process to produce invert cane sugar for packaged foods.
Corn syrup is produced by removing the starch from the corn kernel, mixing it with hydrochloric acid and applying heat under pressure. This process converts the starch molecules to sugar. The syrup is filtered for impurities and evaporated to remove excess water. Store-bought corn syrup is dextrose which is 75% the sweetness of sucrose.
High Fructose Corn Syrup: Developed to create a sweeter corn syrup to use in place of granulated sugar in processed foods and soft drinks. Corn syrup goes through a series of enzyme applications and heat to convert the dextrose to fructose. The longer the process, the higher the concentration of fructose and the sweeter it is.
Fruit nectars (such as agave) and tree saps (such as maple) are extracted from the plant and boiled to remove water and concentrate the natural sugars into a syrup. Raw syrups are less refined (heated at lower temperatures and less filtered) than regular syrups.
Raw Honey: Honeycombs are placed in a centrifuge to separate the honey from the comb. The extracted honey passes through a sieve to remove wax particles and debris. The honey is heated to 120° to melt crystals and filtered again. This is when raw honey is bottled. It’s thicker than processed honey and likely to have a milky appearance. It contains natural enzymes and other nutrients such as antioxidants. About 5% of commercial honey is bottled in this raw form.
Refined Honey: Raw honey is put through a flash heating at 165°, paper filtering and flash cooling before bottling. The process creates a clearer, thinner liquid compared to raw honey but has no nutrient properties. Honey is 40% fructose, 30% glucose and 20% water.
The take-away is get the bulk of your carbohydrates from whole, unprocessed foods and keep added sugars to a minimum. Consume healthy proteins and fats along with healthy carbohydrates to guard against over-consuming carbs as a whole.
When choosing products with added sugars, be skimpy in consumption and choose wisely. Less added sugar is always better than more and less processed is always better than more processed. When adding sweeteners during food prep, consider reducing the amount or omitting whenever possible.
Sources: howstuffworks.com; quora.com; madehow.com