Ultimate Guide to Carbohydrates: Expert Q&A with Dr. Grant

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Ask the Science Team: All About Carbohydrates with Dr. Lucas Grant in Skelmersdale

For this month’s Ask the Science Team post, we had the pleasure of speaking with Dr. Lucas Grant, the principal scientist at Unicity, right here in Skelmersdale. He shared valuable insights on all things carbohydrates—their benefits and downsides, the importance of prioritising complex carbs over simple ones, and much more. Check out the Q&A below to understand how carbohydrates work and their impact on your overall health and wellness.

What is a carbohydrate?

A carbohydrate is a molecule comprising carbon, hydrogen, and oxygen. In our bodies, carbohydrates break down through cellular processes to create energy. They are crucial to our diet as they provide the energy we need to function effectively. Even our brains require carbs to perform at their best.

However, in today’s world filled with processed foods, many people consume too many processed carbs, which aren’t good for our health. Broadly speaking, there are two main types of carbohydrates: simple and complex. We should be prioritising 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, while examples of disaccharides include sucrose (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, which can lead to weight gain if consumed in excess and without sufficient physical activity.

This quick digestion occurs because glucose is the main energy molecule in humans, and most simple carbohydrates break down rapidly into glucose. This can lead to a swift rise in blood sugar levels, which is why it’s crucial to manage our intake of simple carbs.

On the flip side, complex carbs are made up of oligosaccharides and polysaccharides—longer chains of sugar molecules. Examples include fibre and starch. Generally, complex carbs cause a slower rise in blood glucose levels due to the chemical bonds between the sugar molecules needing to break down before absorption. Some types of fibre form a gel-like substance in the gut, helping you feel fuller for longer periods, which aids in weight management and helps maintain normal, healthy blood sugar levels.

Foods high in fiber:

  • Fruits such as apples, bananas, oranges, raspberries, and strawberries
  • Nuts and seeds like chia seeds, flax seeds, almonds, pistachios, and 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 quicker than complex carbs, potentially leading to overeating and weight gain. Simple carbs can also cause spikes in blood sugar and insulin levels, something we should avoid to prevent undesirable effects on the body’s tissues over time.

Complex carbs, on the other hand, are digested slowly, keeping you fuller for longer and providing a steady release of glucose into the bloodstream. This results in a moderated insulin response.

What is the glycemic index?

The glycemic index (GI) helps us understand the healthiness of a carbohydrate. It rates foods based on their effect on blood glucose compared to pure glucose. A higher GI value indicates a larger spike in blood sugar levels, while a lower GI value suggests a slower effect.

For better health, choose foods with a lower glycemic index, often whole foods high in fibre like apples, beans, lentils, and broccoli. High-GI foods include easily digested items like cookies, cakes, and French fries. Even some healthy-seeming options, like sweetened dairy products, certain fruits, and whole-wheat breads, can have a high GI.

Easy swaps for a more controlled blood glucose response:

  • 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 your day with whole grains and use whole or multigrain breads for snacks and lunches. Check ingredient lists on cereals or bread to make sure whole grain is listed first.

Another easy way to get enough of the right carbs is to keep the skins on vegetables and fruits when eating them, as the peels are generally high in nutrients. For instance, a whole apple contains up to 332% more vitamin K and 115% more vitamin C than a peeled apple. The peels also typically contain more fibre.

What kinds of foods should I avoid?

Avoid anything with lots of added sugars, including soda, baked treats, and fruit juices. Also, limit your intake 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, aim to fill up around half to two-thirds of your meals with healthy carbs, particularly from vegetables or higher-nutrient carbs like beans, brown rice, or quinoa.

When examining nutrition labels, look at the “total carbohydrates” section. Total carbs are broken down into sugars and fibres. Most people don’t get enough dietary fibre, so focus on foods with high fibre content and avoid those with added sugars.