Nutritionist Robyn Johnson, RDN answers a few of our most asked questions about carbs, sugar and more:
Clarifications on confusing terminology: Sugar, Carbs, Glycemic Index, Glycemic Load
It is well documented that sugar is a major factor in the obesity epidemic and development of chronic disease (1-3). Most people know that sugar reduction is a step towards better health but the word “sugar” can be confusing. Does sugar just means cakes and candies? Are carbs sugar? Does fruit count as sugar? Oh it’s bread and pasta too? What about rice and quinoa? Are they all the same? Our Nutritionist is here to fill us in.
We’re going to answer all of those questions today. We’ll cover sugar and carbohydrate basics and delve into some other terms that are often brought up with the sugar talk like glycemic index and glycemic load.
Ok, let’s first discuss the basics of sugar and carbohydrates.
Carbohydrates are one of three macronutrients (the others being protein and fat) but not all carbs are created equal. Common sense tells us a snickers bar and a carrot are not the same but they are both majority carb-based. All carbs (snickers or carrots) get digested and broken down into sugar (aka glucose) which increase blood glucose and insulin levels. This process allows glucose to enter our cells and provide energy. Excess glucose will be stored backup energy or as body fat.
So what’s the difference between carbs?
Some forms of carbs will increase blood sugar levels very quickly while others take a slower pace. More processed forms of carbs (like snickers) will rapidly spike blood sugar while whole, food and fiber loaded carbs will rise at a slower pace. The foods that rapidly spike blood sugar are classified as having a high glycemic index (GI), while slow-to-rise-blood sugar-foods have a low GI. GI is simply a way to quantify how fast a specific food will raise blood sugar levels. The link at the bottom of this article provide examples of low, medium and high GI foods. Carbs with a low GI generally have more fiber, fat or protein and therefore, are more slowly digested. This leads to a slower increase in blood sugar and often times, lower insulin levels. Research has shown diets composed of mostly low GI foods can help improve insulin sensitivity (4).
Classifications for GI:
Low = 55 or less
Medium = 56-69
High = 70 or more
Now, let’s talk about glycemic load (GL).
GL takes into account how much of the food is consumed. That is a key piece missing with GI and can misguide some people. An example of why this matter is the vegetable, carrots. If you look at the GI of carrots, it’s 39. This is fairly close to the GI of whole wheat spaghetti at 42. Now, when you factor in quantity and make those foods equal in amount, you’ll see a much bigger gap. Carrots have a GL of 2, while whole wheat spaghetti has a GL of 17. Now you can clearly see which food is healthier. If you’re going to use these tools for food decisions, GL is a better measurement to follow than GI because it incorporates quantity.
Classifications for GL:
Low = 10 or less
Medium = 11-19
High = 20 or more
What does GI or GL have to do with health and disease risk?
Research has shown diets lower in GI and GL have decreased risk for chronic disease development such as diabetes, cardiovascular disease and obesity (5-8). Do you have to count these GI and GL measurements for success? Absolutely not. Simple building a foundation of real food with vegetables and fruits being your main source of carbs will automatically make the high to low GI and GL swaps for you. Plus, you’ll be consuming a variety of vitamins and minerals in those foods which support your health even more. Don’t let these terms intimidate you. They are tools to use if needed but if you’re not one to track or count things related to food, this may not be a tool for you. If you are a number person, we have provided extra resources for you below.
- Glycemic Index and Glycemic Load of Foods here
- Search a specific food for a Glycemic Index rating here