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Carbohydrates - What they are, and how to make healthy choices.

You are what you eat. Our body requires food for energy, building and repairing and  regulating chemical processes. Food can be divided into macronutrients - the nutrients which our body requires in relatively large amounts. The three primary macronutrients are protein, carbohydrates and fat, each of which contain a certain amount of calories and serve to support various processes in the body.


Carbohydrates are our body’s main fuel source and despite their bad reputation certain carbohydrates are vital to our overall health and longevity. The problem lies mainly in the overconsumption of carbohydrates as well as the type of carbohydrates consumed.


Carbohydrates may be classified as simple or complex. Simple carbohydrates, or sugars, are digested and absorbed more quickly than complex ones and can therefore cause faster rises in blood sugar levels when eaten alone. Simple carbohydrates occur naturally in many foods including fruit, vegetables and dairy products. Naturally occurring sugars such as those found in whole fruit occur within a complex matrix which includes fibre, vitamins and minerals. This impacts the way in which our bodies digest, absorb and respond to the naturally occurring sugars. On the other hand, refined sugars such as table sugar and corn syrup which are typically added to ultra processed foods and beverages enter your blood stream much more quickly as they have been stripped of any natural fibre which would slow down digestion. In fact, whereas individuals who have been diagnosed with type 2 diabetes should avoid refined sugars, whole fruits in their natural form should still be included in their diet. This does not include fruit juices and dried fruits as the natiural form has been changed. 


As the name suggests, complex carbohydrates are carbohydrates which have a complex molecular structure, the building blocks of which are actually many sugar units. Starch and fibre are two types of complex carbohydrates. They are found in plant-based foods such as whole grains, vegetables, fruits and beans and legumes. Like sugar, starch is a used as a source of energy in the body as both ultimately broken down to glucose which is either used immediately for energy or stored in the liver and muscle to supply energy at a later time.


Fibre is a ‘special’ type of carbohydrate which your body cannot digest unlike other carbohydrates. its role is not in providing energy to our cells, but has a variety of crucial functions which are increasingly being recognised as central to our overall health and longevity. Fibre has long been known to promote regular bowel movements and prevent constipation as well as to help you feel full for longer. Certain types of fibre act as a food source for your gut microbiome - the trillions of micro-organisms living inside our digestive system - which play a crucial roles in digestion, immunity, nutrient absorption as well as the risk of chronic disease. Including a variety of natural fibre in your diet helps lower cholesterol, reduces the risk cardiovascular disease, aids with blood sugar control and is associated with a lowered risk of certain types of cancer. It is recommended to consume at least 14g of fibre for every 1,000 calories consumed, per day.



Aside from fibre there is no specific amount of carbohydrates a person should consume. Individuals would firstly want to know the approximate amount of calories they should be consuming per day, the total amount of protein they should be consuming and from there can deduce the proportion of carbohydrates that would suit them. Different individuals will require different amounts, typically depending on their lifestyle - an endurance athlete would require more carbohydrates than a sedentary individual in order to perform at their best.  Additionally individuals have very unique responses to the same foods - a trait which may be monitored using a continuous glucose monitor. 


Despite the bad name carbs have with respect to weight gain, it is the overconsumption of calories that increases your body fat and not simply the consumption of carbohydrates. The problem with carbohydrates is that refined and added carbohydrates are typically found in ultra processed foods which are highly calorific, often not filling, and easy to over consume without any of the benefits found in whole foods. 


As described above, carbohydrates are very diverse and we must chose our carbohydrate sources wisely. Focus on eating a variety of whole fruit and vegetables, choose whole grains over refined grain, include beans and legumes, and limit refined and added sugars. 


If you would like to test your personal risk factors for developing chronic diseases of ageing, and find out if you have high markers of inflammation find out more about the Longevity Annual health check and download the longevity doctor guide to healthy living.

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