Understanding Carbs: The Importance of Carbohydrates in a Healthy Diet
WHAT ARE CARBS?
Carbohydrates, or carbs for short, have been the subject of debate and confusion in recent years. Some people view them as the enemy, blaming them for weight gain, poor health, and chronic diseases like diabetes and heart disease. While others argue they are an essential part of a healthy diet, providing energy and important nutrients that our bodies need to function properly.
So, which is it? Should we be avoiding carbs at all costs, or embracing them as an important part of our diet? The truth lies somewhere in between. Here, we will take a closer look at carbs, and why you need them in your diet for optimal health.
BACK TO BASICS
So lets define what we mean by ‘carbs’. Carbs is an umbrella term that is comprised of fibres, starches, and sugars, found in fruits, vegetables, grains, legumes, and added sugars. They are one of three macronutrients that make up our diets, along with protein and fat. Unlike protein and fat, carbs are not considered an essential macronutrient, with no established minimum requirement. However, they play an important role in the body. They act as a primary energy source, and help to control blood glucose, and insulin metabolism, amongst other functions.
When we consume them, our body breaks them down into glucose, which is then used as energy to fuel our cells. Any extra glucose in the bloodstream can be stored in the liver or muscles as glycogen, which the body can use when needed. The type of carbs we consume can make a big difference to our energy levels.
Despite the many health benefits of carbs, there are some types that can be detrimental for our health.
SIMPLE CARBS vs COMPLEX CARBS
Depending on their chemical structure, carbs can be categorised into one of two types:
Simple
These are made up of one or two sugar molecules which are quickly digested by the body, leading to a rapid spike in blood sugar levels. This spike in blood sugar is often followed by a crash, leaving you feeling tired and hungry soon after eating. They also typically provide the body with ‘empty calories’, meaning they provide calories with little nutrients. Increased consumption of this type of carb is associated with weight gain. They are found in highly processed foods including, sugary drinks, sweets, and refined grains like white bread and non-wholegrain pasta.
Complex
These are made up of many sugar molecules and are digested more slowly by the body. This slow release of sugar into the bloodstream helps keep blood sugar levels stable, providing a steady source of energy over a longer period of time. They are generally considered healthier than simple carbs, and are found in whole plant-foods including, whole grains, fruits, vegetables, and legumes.
FIBRE
Fibre is a non-digestible complex carb, which plays a crucial role in maintaining good health. It passes through the digestive system relatively intact, without being digested or absorbed. There are two types of fibre:
Soluble
Soluble fibre dissolves in water to form a gel-like substance in the digestive tract. This type of fibre helps to slow down the digestion and absorption of carbs, and in turn, helps to regulate blood sugar levels. It can also help to lower cholesterol levels by binding to cholesterol and preventing its absorption in the body. Sources of soluble fibre include oats, beans, lentils, fruits, and vegetables, including carrots and sweet potatoes.
Insoluble
Insoluble fibre doesn’t dissolve in water and passes through the digestive tract largely unchanged. It adds bulk to stool, which helps to promote regular bowel movements and prevent constipation, and diverticulosis. Sources of insoluble fibre include whole-grain foods, such as whole wheat bread and brown rice, as well as fruits, and vegetables, including broccoli and leafy greens.
Both types of fibre are important for maintaining good health. A diet that is high in fibre promotes bowel regularity, lowers cholesterol levels, improves gut health, reduces inflammation, and has been linked to a reduced risk of several chronic diseases, including heart disease, stroke, and type 2 diabetes (contrary to popular belief). It can also promote a feeling of fullness, making it beneficial for weight management.
It is recommended to consume 30 grams of fibre per day, from a variety of sources. However, many people do not reach these recommendations.
GLYCAEMIC INDEX
Carbs can be classified by their glycaemic index (GI), which is a ranking system for carb-containing foods, based on how they affect blood sugar levels. The GI uses a scale from 0-100. Foods with a high GI are rapidly converted into glucose and cause a rapid spike in blood sugar. Foods with a GI of 70 or higher are considered high GI. Lower GI containing foods are converted into glucose more slowly and cause a more sustained release of sugar into the bloodstream. Foods with a GI of 55 or lower are considered low GI, and those with a GI between 56-69 are considered medium GI.
High GI foods, like simple carbs, can contribute to weight gain and increase the risk of developing type 2 diabetes. In contrast, foods with a low GI, like complex carbs, can help to regulate blood sugar levels and reduce the risk of chronic diseases. Foods that are higher in fibre, protein, and fat, tend to have a lower GI, as they slow down the digestion and absorption of carbs.
The GI can be a useful tool for people with diabetes, as it can help them choose foods that are less likely to spike their blood sugar levels.
INCORPORATING HEALTHY CARBS INTO YOUR DIET
It is recommended in the UK for carbs to make up around 50% of our daily calorie intake, with the remaining coming from fat (around 35%) and protein (around 15%). For an average adult, this means eating around 200-300g of carbs per day. However, will vary depending on age, gender, body composition, activity levels, and health status.
To incorporate healthy carbs into your diet, it’s important to make smart choices. Here are some tips for making healthier carb choices:
Choose whole grains over refined grains. Whole grains like brown rice, quinoa, whole wheat pasta, and whole wheat bread are rich in complex carbs and fibre, making them a healthier choice than refined grains like white bread and non-wholegrain pasta.
Include fruits and vegetables into your diet. These are rich in complex carbs, fibre, and other vital micronutrients that can help to improve your overall health.
Limit your intake of sugary drinks and snacks. These foods are high in simple carbs and can contribute to weight gain and chronic disease. No more than 5% of your daily energy intake should come from free sugars, which are sugars added to foods or drinks (including fruit juices).
BUT WHAT ABOUT KETO?
The ketogenic (keto) diet is a very low carb, high fat diet, which has gained popularity in recent years, mainly due to its successful short-term effects on weight loss. By limiting carb intake, the body is forced to use fat as an alternative energy source, shifting your body into a state of ketosis (burning fat over glucose). However, there are some potential issues with this diet that should be considered. Short term side effects associated with the diet include the ‘keto flu’, including feelings of fatigue, weakness, nausea, and vomiting. However, feelings typically pass after a few days to weeks. Some longer term side effects have also been reported including kidney stones and vitamin deficiency, among others.
A recent 2023 study found a ‘keto-like’ diet could be linked to serious heart health problems in the long run. The diet was associated with higher cholesterol levels, which doubled the risk of heart attacks and strokes. This is likely due to the high consumption of saturated fat intake, from animal products. Due to the diet being so restrictive, it can be difficult to get all the necessary nutrients for good health, including vitamins, minerals, and fibre, likely resulting in nutrient deficiencies and gut issues. While the diet may be beneficial for weight loss in the short term, it is important to consider the likely long-term effects associated with the diet.
It’s important to speak to a healthcare professional, like a nutritionist, before starting a restrictive low-carb diet like keto, to ensure that your diet is balanced and meeting your nutritional needs.
SUMMARY
Overall, it’s important not to be afraid of carbs. They are a key part of a healthy diet, providing the body with nutrients and energy. Instead of demonising or excluding entire food groups, it is advised to make smart choices and opt for complex carbs found in legumes, whole grains, fruits, and vegetables, which will help you to feel fuller for longer, while providing your body with a wide variety of essential nutrients. Ultimately, a balanced diet that includes healthy carbs, along with protein and fat, while limiting refined grains and added sugars, is important for maintaining good health.
References
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7. American College of Cardiology. Low-Carbohydrate High-Fat “Keto-Like” Diet Associated With Increased Risk of CVD. 2023.
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