We have watched carbohydrates ebb and flow in popularity. In this video Dr Kirsty Fairbairn cuts through the confusion and reveals the truth behind this vital nutrient. 

Carbohydrate is a valuable nutrient for both exercise and health. Carbohydrate energises the muscles, heart, liver and brain, delays fatigue and supports gaining muscle. A common mistake we see is that the nutrient is judged based on the food supplying it. Let’s learn how not to do that.

The phrases ‘carbohydrate’ and ‘carbs’ are often used to describe a narrow subset of carbohydrate-containing foods to suit a particular story, when in fact they are very large umbrella terms. There are literally thousands of carbohydrate-containing foods across a wide spectrum; some healthier than others. This only adds to the confusion. We’ll help you separate the wheat from the chaff (pun intended!).

Which carbohydrate-containing foods will help you to eat smarter, feel better, and perform at your peak?

What is carbohydrate?

Carbohydrate is a nutrient found mainly in plant foods. As we eat them we break them down into single sugar units like glucose, before absorbing them into our bloodstream. Carbohydrate is the body’s preferred fuel source for high-intensity exercise. We also use carbs for energy in our brain, our red blood cells, heart, liver and immune system. Carbohydrate is one of the three main macronutrients found in food, along with protein and fat. For every gram of carbohydrate consumed, we get 16-17 kilojoules (4 calories) of energy. This is actually the lowest energy nutrient! In our Types of Energy topic under the previous Energy less, we described more about energy and macronutrients. We store carbohydrate energy as glycogen mainly in our muscles, with some also in our liver.

If you exercise one or more times a day you need a lot more energy and carbohydrate than usual. Eating carbohydrate enhances your ability to exercise at higher intensities. The amount of carbohydrate you need will depend upon the exercise you do, your weight and the intensity and duration of exercise.

Even if you are not a regular exerciser, you still need to eat carbohydrates regularly in your diet for many health reasons and to help your body function optimally. The question is, what foods are the best sources of carbohydrate? We will show you.

What foods contain carbohydrate?

Most of our dietary carbohydrate comes from plants, except lactose which comes from milk. Carbohydrates are made in plants from sunlight energy via photosynthesis. Those carbohydrates are stored in the plant for its own energy needs, or used to build the structure of the plant.

There are three major types of carbohydrate in plants: starch, sugar and fibre. Different parts of plants have different types of carbohydrate in varying quantities, depending on what the plant needs for its own growth and reproduction.

Starch

Starch is a common form of carbohydrate in our diet, usually from the part of a plant where it stores carbohydrate. Corn, peas, beans, potatoes and grains (including rice, oats, wheat and barley) are all good sources of starch. When humans eat starch, our bodies break it down as we digest it, into lots of little glucose or other sugar molecules. We can then absorb those sugars from our gut into our bloodstream and either use them or store them for our own energy.

Sugar

Plants also contain different types of sugars. Fruit is a great example of that. In whole unprocessed fruit, the sugar is stored inside intact cell walls that are built from fibre. Think of a balloon made of fibre with the sugar stored inside. This means the sugar in whole fruit is slower to be digested and released when we eat it, because the fibre balloon makes it harder for our digestive enzymes to get in.

Fibre

Another important type of carbohydrate in our diet is fibre. Fibre comes from the structural part of plant stems, leaves, fruit and seeds. Vegetables, fruit, whole grains, nuts, beans, peas and lentils are all high-fibre foods. While fibre gives us a lot less energy (as kilojoules and calories per gram) than starch and sugar, it gives our gut amazing exercise and is very important to both our gut health and our general health. Fibre is a fantastic nutrient to eat a lot of.

When you think about it, it is a pretty amazing concept that we can use energy that comes from the sun, via plants, to help us live our own lives.

Food processing and carbohydrates

Food processing impacts carbohydrate-containing foods a lot. This is because food processing often removes the fibre from the plant (like processing white bread from wholegrain fibre-rich wheat or rye for example). Another example is processing fruit into fruit juice. The fibre structure or content is changed or entirely removed, meaning the sugar in that plant becomes a lot easier for us to break down during digestion. This makes it much faster for those sugars to hit our bloodstream; when slow release is better for our body. It also means that we can taste the sugar in the processed food much more easily on our tastebuds, which might make us like that food more, and eat and buy more of it.

Generally fruit and vegetables retain much more fibre in their natural, whole and unprocessed form. That is why we recommend eating fresh or frozen fruits and vegetables a lot. Other processed carbohydrate foods like cakes, doughnuts and biscuits have very little fibre, meaning the carbohydrates in them are much easier to access and digest.

What carbohydrate-containing foods are best to eat?

Foods containing wholegrain, natural and minimally processed carbohydrates should make up a lot of anyone’s food intake, whether you are physically active or not. It is important to recognise and choose nutritious carbohydrate food sources for good health. We call these “nutrient dense” foods because they have many other nutrients alongside the carbohydrate and energy. See our Types of Energy topic in the Energy lesson to take the Nutrient Dense test.

We all need to consume a variety of foods to get all the nutrients needed to operate well. Whole fruit, whole vegetables and whole grains are all high in fibre and an important part of a healthy diet. They contain vitamins, minerals and other important nutrients (including antioxidants) that are good for our health. That doesn’t mean that you can’t enjoy a less nutrient-dense food like a doughnut from time to time.

There are some situations where an athlete may find more refined carbohydrate foods useful, such as during busy competition tournaments or meets when your stomach might not tolerate your normal food so well. Easy and quick to digest carbohydrate foods can help meet higher fueling needs. However, try to make sure your dietary carbohydrate comes from nutrient-dense foods most of the time in your usual training diet.

In Summary

Dietary carbohydrate comes in a range of different forms, such as sugar, starch and fibre. Plants are our largest source of nutritious carbohydrate and the less processed the better. Many plants foods (like legumes and beans) provide carbohydrate alongside protein, vitamins, minerals and fibre. Dietary carbohydrates feature in a wide variety of foods around us. Don’t judge carbohydrate the nutrient by the food that supplies it. Some foods that contain carbohydrate are more nutrient dense and higher in fibre than others.

Food processing can change the dietary fibre in a plant food a lot, or remove it completely. This can impact the speed at which those carbohydrates are absorbed into your bloodstream. Slow absorption of carbohydrate into our blood is generally healthier than fast absorption.

Selecting the right carbohydrate-containing food for you should be guided by what your situation is at that point in time, whether you need more nutrients with your carbohydrates and what makes you feel energised and how much exercise you do, at what intensity, and what your health or training goals are. See a specialist Dietitian or Nutritionist for advice tailored to you.