Confused about sugars and carbohydrates?

This is a summary of what carbohydrates and sugars do to our bodies and how to navigate your way around nutrition labelling. 

Firstly carbohydrates are not bad! No one nutrient is good or bad all nutrients confer different physiological effects that can contribute to health. Yes, it is true that when we eat more carbohydrate than the body needs in a meal it will store the reserve as adipose tissue and it will do the same when we eat too much protein in one meal. This is because the body is an energy efficient system set up for feast and famine and it will store what it doesn’t need now for later. 

The body needs a variety of different nutrients to maintain health, including carbohydrates which provide the main energy source (glucose) for blood and our brains. Yes glucose can be made by breaking down proteins but at the cost of losing muscle mass which can influence our metabolic rate; and fat can be broken down into ketones which can fuel the brain but it is not the preferred route, ask any type 1 diabetic who has gone into ketosis whether it was a pleasant experience and I am sure the answer will be no. Because the body has a backup system to protect, when carbohydrate is in short supply carbohydrates are not classified as an essential nutrient this can be where the confusion begins. However remember our bodies are a finely tuned system that evolved to survive in a feast and famine environment. The only problem is that this primal setting has not changed in a feast and feast environment. Carbohydrates may not be classified as essential but that doesn’t mean the whole body does not work better without them. Portioning, type and timing are key factors to consider when choosing carbohydrates and this will vary person to person depending on age, gender, health and lifestyle.


Aim for 1/3 -1/4 plate being carbohydrates and this can include starchy vegetables like potatoes, squash and pumpkins. Aim for one type of carbohydrate per meal avoid double carbs e.g. rice and a naan, spaghetti and garlic bread, pizza and dough balls.


Carbohydrates exist in different structures: short, long, and branched chains which all confer different physiological effects much of which is influenced by the fibre content of the foods that they are in. The main sources of carbohydrates are grains, some vegetables and lentils (known as starchy carbohydrates). When these foods are consumed in their whole state the fibre around the glucose molecules makes it harder to liberate the glucose into the bloodstream thus releasing it at a much slower rate than processed grains. For example, some breakfast cereals are grains that have been broken down and reformed, thus changing the structure of the carbohydrate and making it easier for the body to digest and access the glucose which will then enter the blood stream much quicker. This will cause blood glucose levels to rise sharply and then drop lower than baseline which can leave us feeling tired and hungry. Eating foods that have added refined sugars will only exacerbate this response. 

What we are aiming to do is keep our blood glucose levels steady and avoid peaks and troughs which can drive us to eat more. Refined sugars are often added to foods to enhance their palatability and in doing so this can drive us to eat more. 

One refined sugar that has been studied and shown to have an impact on our waistlines is high fructose corn syrup. High fructose corn syrup is a common ingredient in fizzy drinks and is being widely used in other products as a sweetening agent. Fructose stimulates the taste buds on our tongue to produce the sweet sensation thus increasing its desirability. But before we get fearful of fruit which is high in fructose let’s just remember that high fructose corn syrup has been stripped of its fibrous outer layer and if you are drinking a 2L bottle of fizzy drink a day the portion of refined sugar is excessive. 

We don’t need refined sugars but the body can benefit from including non-refined carbohydrates as part of nutritionally balanced meals. Refined sugars stimulate our taste receptors and combined with fat and salt trigger the reward system in our brains to drive our appetite. Have you ever noticed that foods high in refined sugar often leave you feeling unsatisfied but craving for more? 


What the eatwell plate does not show is how our need for carbohydrate changes over the day. Think about it; if carbohydrate is your main energy source when will you need more of it: In the morning, middle of the day or in the evening? Most of the population could benefit from less carbohydrate in the evening as the main activity will be resting. Specialised diets are designed for athletes as the type and timing of carbohydrates is central to maintaining energy levels and reducing the risk of injury.

Here are five simple guidelines to navigate your way around carbohydrates:

  • Don’t go to the supermarket hungry as you will find yourself down the centre aisles amongst the sweet stuff. Our desire for high fat and sugar foods is much stronger when we are hungry.
  • Choose unrefined grains (whole); less processing means more fibre which has health benefits.
  • Eat fruit whole and keep it in moderation (one to two servings a day).
  • Pay attention to the added sugar content on food labels, this is in the form of free sugars (sugars that do not naturally occur in the food) added to enhance taste. It’s worth looking at the ingredients list as well, as sugar comes in lots of different forms: corn syrup, maltodextrin, dextrose, glucose-fructose syrup, malt syrup, molasses...
  • Have more carbohydrate in the early and middle part of the day and a smaller portion in the evening. This dietary pattern will not suit those who are more active in the evening due to sports or shift patterns. For the best advice, it is worth consulting a dietitian.

The views expressed in this article are those of the author. All articles published on Nutritionist Resource are reviewed by our editorial team.

Share this article with a friend
Stratford Upon Avon, CV37
Written by Jo Withers, Registered Dietitian/ Nutritionist and Yoga teacher
Stratford Upon Avon, CV37

I specialise in disordered eating but I am experienced in treating a range of diet related issues and have a specialist interest in sports nutrition. As a registered dietitian I use the most up to date evidence based practice to devise individualised diet therapy.

Show comments

Find a nutritionist dealing with Healthy eating

All nutrition professionals are verified

All nutrition professionals are verified