Ask the Science Team: All About Carbohydrates with Dr. Lucas Grant in Rawtenstall
For this month’s Ask the Science Team post, we had the pleasure of sitting down with Dr. Lucas Grant, principal scientist at Unicity, to delve into the world of carbohydrates. We discussed the benefits and downsides of carbs, why you should prioritize complex carbs over simple carbs, and much more. Take a look at the Q&A below to understand how carbohydrates work and how they affect your overall health and wellness.
What is a carbohydrate?
A carbohydrate is a molecule that consists of carbon, hydrogen, and oxygen. Carbohydrates are broken down in the body and undergo cellular processes to generate energy. They are integral to our diet as they provide the energy necessary for us to function. Even the brain needs carbs to operate optimally.
However, in our overly processed world, many people consume too many processed carbs, which aren’t beneficial for us. Generally, there are two main types of carbohydrates: simple and complex. We should be prioritizing complex carbs.
What is the difference between simple and complex carbohydrates?
Simple carbs consist of monosaccharides (single sugars) and disaccharides (double sugars). Examples of monosaccharides include glucose, fructose, and galactose. Examples of disaccharides include sucrose (table sugar), lactose (milk sugar), and maltose. Sucrose is actually a sugar combination of glucose and fructose. Simple carbs are very easy for your body to digest and absorb, and can result in weight gain if consumed in abundance without enough exercise.
This is because glucose is the primary energy molecule in humans, and most simple carbohydrates are broken down into glucose, converted for use as energy, or stored for later. This can occur more rapidly than other carb sources, emphasising the need to monitor our intake of these.
Complex carbs are composed of oligosaccharides and polysaccharides—longer chains of sugar molecules. Examples include fiber and starch. Generally, complex carbs cause a slower rise in blood glucose than simple carbohydrates, as the chemical bonds between these sugar molecules must be broken before they can be absorbed into the bloodstream. Some types of fiber can swell and form a gel-like structure in the gut, keeping you fuller for longer periods. This aids in weight management and supports normal, healthy blood sugar levels.
Humans lack the digestive enzymes to break down most fibers, so we aren’t able to digest these like other carbs. Our microbiome—the beneficial bacteria in our gut—are predominantly responsible for extracting nutrients from fiber for us and can even convert fiber into other vital energy sources, better supporting weight management.
Conversely, we possess the digestive enzymes to break down starch. Starch consists of chains of glucose. Consequently, foods high in starch typically cause a greater rise in blood glucose than those rich in fiber. Thus, opt for high-fiber foods over high-starch foods. And if you’re craving starch, choose better starch sources. For instance, whole grain bread is better than white bread, or opt for food sources with more resistant starch, such as legumes, as resistant starch behaves more like fiber and isn’t rapidly digested.
Foods high in fiber:
- Fruits such as apples, bananas, oranges, raspberries, and strawberries
- Nuts and seeds—chia seeds, flax seeds, almonds, pistachios, sesame seeds
- Beans, especially navy and white beans
- Whole grains
Foods high in starch:
- Corn
- Peas
- Rice
- Breads
- Potatoes
Why are complex carbs better for us?
Simple carbs break down faster and leave you hungry in a shorter period of time than complex carbs do. This may lead to eating more simple carbs, which will turn into fat if not used for energy. Simple carbs can also cause a spike in blood sugar and a subsequent spike in insulin levels, the hormone that helps regulate blood sugar. This is something we want to avoid, because over time, it can cause many undesirable effects on the body’s tissues.
Complex carbs, on the other hand, are digested more slowly than simple sugars, keeping you fuller for longer periods. They supply a steadier release of glucose into the bloodstream, causing a much slower rise in blood sugar than simple carbs, resulting in a moderated insulin response.
What is the glycemic index?
Sometimes we start to think that all foods containing simple carbs are bad and that all foods with complex carbs are good, but that’s not always accurate. Simple carbs found in whole fruits, milk, and other generally healthy foods contain essential vitamins, minerals, and other nutrients. The foods we should be avoiding are processed foods, like sugary drinks and candy.
While it’s true that complex carbs are better for us, we must also be cautious of complex carbohydrates that are refined and processed, meaning a lot of nutrients like fiber, minerals, and vitamins are removed. This includes white bread and white rice.
This is where the glycemic index becomes helpful. It rates how “healthy” a carb is going to be for you. Foods are given a value to indicate their effect on blood glucose (sugar) relative to the effects of pure glucose. A higher number indicates the food would cause a larger spike in blood glucose. A lower number indicates the food has a smaller or slower effect on raising blood glucose.
For better health, select foods with a lower glycemic index. These are often whole foods high in fiber, like apples, beans, lentils, and broccoli. High-glycemic index foods often include foods that are easily and quickly digested, like cookies, cake, and French fries, but there are others that might surprise you. Sweetened dairy products like yogurt, fruits like watermelon and pineapple, and even some whole-wheat breads have a high glycemic index.
Here are some easy swaps for a more controlled blood glucose response (and to avoid that large glucose spike followed by a sugar crash):
- Instead of white rice, eat brown rice
- Choose multigrain bread instead of white bread
- Opt for broccoli or leafy greens over corn
How do I get more of the right carbs in my diet?
To ensure you get the most out of your carbs, start the day with whole grains and use whole or multigrain breads for snacks and lunches. Check the ingredients list on your cereal or bread and make sure whole grain is listed first.
Another easy way to ensure you’re getting enough of the right carbs is to keep the skins on when eating vegetables and fruits. The peels are generally very high in nutrients. For example, a whole apple contains up to 332% more vitamin K and 115% more vitamin C than a peeled apple. These peels typically contain more fiber, too.
What kinds of foods should I avoid?
Avoid anything with lots of added sugars, including soda, baked treats, and fruit juices. Also avoid consuming an excessive amount of refined grains such as white bread, white rice, pasta, and crackers.
How many grams of carbohydrates should I eat per day?
According to the Dietary Guidelines for Americans, the average adult should aim to consume between 900 to 1300 calories (45–65% of calorie intake) from carbs per day.
As a general rule, you should fill up around half to two-thirds of your meals with healthy carbs. A lot of those should come from vegetables or higher-nutrient carbs like beans, brown rice, or quinoa.
Take a look at the “total carbohydrates” section on nutrition labels of foods you eat regularly. Total carbs are broken down into sugars and fibers. Most people don’t get enough dietary fiber, so try to focus on foods with high fiber content and avoid those with added sugars.