Carbohydrates are one of the three macronutrients (the others being protein and fat) that are essential for providing energy and supporting various bodily functions.

When we consume carbohydrates, they are broken down into glucose (a simple sugar) in the digestive system, which then enters the bloodstream and is transported to cells throughout the body.

The body uses glucose as its primary source of energy, and it is particularly important for the brain and nervous system. When glucose enters the cells, it is either used immediately for energy or stored in the liver and muscles as glycogen for later use.

Insulin, a hormone produced by the pancreas, plays a crucial role in regulating the amount of glucose in the bloodstream. When blood sugar levels rise after a meal, insulin is released to help cells absorb and use the glucose.

However, if there is an excess of glucose in the bloodstream and cells are already adequately fuelled, insulin signals the liver and muscles to store the excess glucose as fat. This is why consuming too many carbohydrates, especially refined carbohydrates like sugar and white flour, can lead to weight gain and other health problems.

Simple carbohydrates and complex carbohydrates can be thought of as different types of fuel for the body, much like fuel for a car.

Simple carbohydrates are like the quick-burning fuel that you put in a sports car to give it a quick burst of energy. These are the sugars found in chocolate, sweets, and other processed foods. Just like how a sports car can quickly accelerate but runs out of fuel faster than a regular car, simple carbohydrates provide a quick burst of energy but leave the body feeling hungry and low on energy soon after.

On the other hand, complex carbohydrates are like the slow-burning fuel that you put in a hybrid car. These are the carbohydrates found in whole grains, vegetables, and legumes. Just like how a hybrid car can run for longer on less fuel and has a more consistent speed, complex carbohydrates provide a steady supply of energy to the body and keep you feeling full for longer.

So, while both simple and complex carbohydrates provide fuel for the body, the type of carbohydrate and the timing of consumption can have a significant impact on how you feel and function throughout the day.

1g of carbohydrate provides 4 calories (the same as protein with fat being 9). More recently, they’ve developed a bad reputation as there is a wide spread opinion that restricting carbs will lead to your body using it’s own fat stores as energy which in turn aids fat loss. Although this has some truth to it, the analogy hopefully displays how it’s not necessarily the restriction of carbohydrates but more so the understanding and eating the right types of carbohydrates alongside exercise and a strong diet in other areas.

Types of carbohydrates

The most basic breakdown is to split carbs into 2 groups; simple and complex.

Simple carbohydrates are sugars formed of one or two molecules which means they can be broken down quickly. The most commonly found types of sugars to look for on food labels are Glucose, Fructose, Sucrose and Lactose which you’ll find in sugary processed foods such as chocolate or a ready meal but also in fruits and milk. Simple carbohydrates are absorbed and used for energy quickly by the body which is why you’ll see endurance athletes sucking on a gel pack of syrup mid marathon or even a bodybuilder with low bodyfat drinking a can of coke or flavoured milk before training.

Simple carbohydrates therefore can have their place in any nutrition plan, especially considering a lot of fruits contain them but have other health benefits. If trying to lose weight it’s probably best to avoid them or at least restrict them to eating just low calorie fruit (berries, melons, lemon, apple, grapefruit) for example. Why? Firstly, simple carbohydrates can deliver a quick spike of energy followed by a feeling of a crash, particularly on a low calorie diet where other carbohydrates have been restricted. Secondly, simple carbohydrates are less filling than their counterpart complex carbohydrates as the don’t pack as many nutrients and are digested faster.

Complex carbohydrates are sugar molecules branched together to make longer chains of molecules, which in turn means they take longer to break down. These chains form fibres or starch with most foods high in complex carbohydrates containing both. Fibre is great for digestion and it also helps keep you fuller for longer. As already mentioned, complex carbohydrates are slower to digest so give a slower release of energy. They also provide vitamins and minerals that are good for the body. Complex carbohydrates are found in food such as oats, beans, whole grains, vegetables, pasta and rice. As with simple carbohydrates some foods are “better” than others. For example, white pasta is refined which makes the food lose some of the vitamins and minerals so unrefined food such as brown pasta is better for us nutritionally.

So what does this mean?

If you’re training, you need to fuel your body the right way. Choosing complex carbohydrates will give you energy to train. Avoiding simple carbohydrates will reduce the “empty” calories you’re consuming and are likely to turn to fat if your glycogen stores are full, unless of course you train immediately after or while consuming them but even then you need to be smart about it; eating a whole tub of Ben and Jerry’s containing 1350 calories and 125g sugar probably isn’t the best pre-workout meal.

You should get all the carbohydrates you need through diet but you can supplement your carbohydrate intake. Sometimes it’s best through convenience, and sometimes it may be that on a strict diet, you don’t want to eat 50g oats (containing 190 calories) to get your 30g carbohydrates you need to perform in the gym so taking 30g pure carbohydrates (120 calories) keeps you performing without the extra calories.

Carbohydrate supplements to look for…

Instant Oats (Fine Oats)

In our opinion at Whey It Up, oats are God tier foods as 100g of oats provides around 380 calories, 60g of complex carbohydrates and 12g of protein. If bulking, it’s easy to eat 150g oats twice a day to instantly deliver over 1000 calories, 180g carbohydrates and 36g protein. If cutting, oats pre and post workout (when majority of your carbohydrates should be consumed) are a great option.

Instant oats are just oats that have been blended to a fine powder. So why buy? Well, you can build your own “weight gainer” shake by mixing 100g instant oats with a scoop of whey post workout, for a convenient weight gain snack or for a meal replacement if cutting. They’re also very cheap!

Highly Branched Cyclic Dextrin (HBCD, Cluster Dextrin)

HBCD (patented version: Cluster Dextrin) is the most popular carbohydrate used in intra-workout supplements and is also the most expensive. The main reasons are firstly the rapid speed of digestion which leads to zero bloat or digestive discomfort and secondly, it tends to give a more sustained energy over time compared to other forms of carbohydrate which can see more of a “spike” of energy after ingestion. HBCD also has the added benefit of aiding the absorption of other nutrients so if consuming some EAAs or BCAAs alongside then these will be digested more efficiently too.


Vitargo is a world patented form of carbohydrate produced from starch and manufactured to have a high molecular weight which means it moves through the digestive tract quicker to aid absorption and decrease any form of bloat or “fullness” you may get from consuming a large amount of carbohydrates. It is expensive and when choosing between this and cyclic dextrin most would opt for the HBCD.

Waxy Maize Starch

Waxy Maize Starch is largely considered better than Maltodextrin and Dextrose, but not as good as Vitargo or HBCD. It is made from cornstarch which you can pick up a lot cheaper from a supermarket…


Maltodextrin is a processed carbohydrate formed from rice, wheat, corn or potato starch. It’s classified as a complex carbohydrate but it does give a fast release energy due to the fact it has a short molecular chain. It is absorbed extremely quickly which can create a “spike” in blood sugar levels and therefore energy and is generally considered a poor form of carbohydrate due to this. You may experience some bloating or some form of “crash” in energy if consuming high amounts but this will differ between individuals. Maltodextrin is relatively cheap.


Dextrose is a simple carbohydrate found in lots of processed foods. It is extremely similar to glucose. It is absorbed quickly and will give a fast burst of energy however those that are intolerant to gluten may prefer this to maltodextrin due to maltodextrin’s ingredients. You may experience some bloating or some form of “crash” in energy if consuming high amounts but this will differ between individuals.

To read more about nutrition and how many carbohydrates you should be consuming, take a look at our complete guide to nutrition.