Ask the Science Team: Insights on Carbohydrates with Dr. Lucas Grant from Unicity
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. From uncovering the benefits and drawbacks to understanding why complex carbs should be prioritized over simple ones, Dr. Grant sheds light on these vital nutrients. Dive into the Q&A below to gain a comprehensive understanding of how carbohydrates function and their impact on your overall health and wellness.
What is a carbohydrate?
A carbohydrate is a molecule comprised of carbon, hydrogen, and oxygen. Carbohydrates are broken down in the body and undergo cellular processes to generate energy. They play an essential role in our diet as they furnish the energy needed for daily functioning. Interestingly, the brain also relies heavily on carbs to operate optimally.
In today’s world, particularly here in Preston, the ubiquity of processed foods has led many people to consume excessive amounts of processed carbs, which aren’t beneficial. Broadly, carbohydrates are categorized into two main types: simple and complex. Emphasizing the intake of complex carbs is crucial.
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 (commonly known as table sugar), lactose (milk sugar), and maltose. Sucrose is actually a combination of glucose and fructose. Simple carbs are easily digested and absorbed by the body, potentially leading to weight gain if consumed excessively without adequate physical activity.
Complex carbs, on the other hand, are composed of oligosaccharides and polysaccharides—longer chains of sugar molecules. Examples include fiber and starch. Generally, complex carbs induce a slower rise in blood glucose compared to simple carbohydrates, as the chemical bonds within these sugar chains need to be broken down before absorption into the bloodstream. Certain fibers can swell and form a gel-like substance in the digestive tract, aiding in prolonged satiety, weight management, and maintaining healthy blood sugar levels.
Humans lack the digestive enzymes necessary to break down most fibers. Consequently, these fibers are not digested in the same manner as other carbs. Our gut microbiome—the beneficial bacteria in our digestive system—plays a pivotal role in extracting nutrients from fiber. These bacteria can even convert fiber into other vital energy sources, which further supports weight management.
On the other hand, we do possess the digestive enzymes required to break down starch. Starch consists of glucose chains, leading to a more significant increase in blood glucose levels compared to high-fiber foods. Thus, it’s advisable to choose high-fiber foods over high-starch alternatives. For example, opt for whole grain bread over white bread or select food sources with resistant starch, such as legumes, as resistant starch behaves similarly to beneficial fiber and isn’t rapidly digested.
Examples of High-Fiber Foods:
- Fruits such as apples, bananas, oranges, raspberries, and strawberries
- Nuts and seeds, including chia seeds, flax seeds, almonds, pistachios, and sesame seeds
- Beans, especially navy and white beans
- Whole grains
Examples of High-Starch Foods:
- Corn
- Peas
- Rice
- Breads
- Potatoes
Why are complex carbs better for us?
Simple carbs break down quickly, potentially leaving you feeling hungry sooner than complex carbs. This may lead to overconsumption, with excess carbs being converted into fat if not used for energy. Simple carbs can also cause rapid blood sugar spikes followed by increases in insulin levels, the hormone that regulates blood sugar. Over time, this can have detrimental effects on bodily tissues.
Conversely, complex carbs digest more slowly, ensuring prolonged satiety. They provide a steady glucose release into the bloodstream, resulting in a gradual rise in blood sugar levels and a moderated insulin response.
What is the glycemic index?
It’s a common misconception that all foods containing simple carbs are bad and all foods with complex carbs are good. This isn’t always the case. Simple carbs in whole fruits, milk, and other generally nutritious foods are packed with essential vitamins, minerals, and other nutrients. The real culprits to avoid are processed foods loaded with added sugars, like sugary drinks and candy.
While complex carbs are generally better for us, be cautious of refined and processed complex carbohydrates, which lose significant nutrients like fiber, minerals, and vitamins. Examples include white bread and white rice.
The glycemic index (GI) can be a helpful tool. It rates the health impact of carbs by assigning values that represent their effect on blood glucose relative to pure glucose. A higher GI value indicates that the food causes a larger blood glucose spike. Conversely, lower GI values suggest a slower and smaller effect on raising blood glucose levels.
For better health, lean towards low-GI foods. These often include whole foods rich in fiber, like apples, beans, lentils, and broccoli. High-GI options, like cookies, cake, and French fries, should be avoided, although some unexpected foods, such as sweetened dairy products, watermelon, pineapple, and certain whole-wheat breads, also carry high GI values.
Easy Swaps for Controlled Blood Glucose Response:
- Instead of white rice, eat brown rice
- Choose multigrain bread over white bread
- Opt for broccoli or leafy greens over corn
How do I get more of the right carbs in my diet?
To maximize carbohydrate benefits, start your day with whole grains and choose whole or multigrain breads for snacks and lunches. Check the ingredients list on cereal or bread packages to ensure whole grain is listed first.
Another easy method to boost the right carb intake is to keep the skins on vegetables and fruits. The peels generally contain higher nutrient levels. For example, a whole apple contains up to 332% more vitamin K and 115% more vitamin C than a peeled apple, along with more fiber.
What kinds of foods should I avoid?
Avoid foods with large amounts of added sugars, including soda, baked treats, and fruit juices. Refrain from consuming excessive amounts of refined grains such as white bread, white rice, pasta, and crackers.
How many grams of carbohydrates should I eat per day?
The Dietary Guidelines for Americans recommend that the average adult should aim to consume between 900 to 1300 calories (45–65% of total calorie intake) from carbs daily.
As a rule of thumb, aim to fill around half to two-thirds of your meals with healthy carbs, primarily from vegetables or nutrient-dense carbs such as beans, brown rice, or quinoa.
When checking nutrition labels, focus on the “total carbohydrates” section, which is broken down into sugars and fibers. Most people don’t consume enough dietary fiber, so prioritize foods high in fiber and avoid those with added sugars.