Is Sugar at the Root of Health Concerns?

Is Sugar at the Root of Health Concerns?

It seems that every year, there is a nutrient to blame for the global populations’ ‘unhealthiness’. The 1970s and 80s praised low-calorie, low-carbohydrate (sugar) diets through the ‘Atkins’ and other similar diet trends. The 90s put more emphasis on low-fat intake and low-fat product alternatives grew exponentially. Dean Ornish advocated a low-fat, vegetarian diet and published his book ‘Eat More, Weigh Less’ in 2000. The ‘South Beach’ diet of 2003 promoted high protein and you guessed it, low carbohydrate intake. More recently, ketogenic diets (high fat, low carb), gluten-free (no wheat, barley, rye) and veganism (no animal produce) are more commonly adopted… Who knows what’s to come? 

A common theme amongst these diets is the minimisation of sugar-containing foods in an attempt to promote weight loss. Carbohydrates are, scientifically speaking, compounds made up of sugars, starches and dietary fibre. They come in different shapes, sizes and digestion patterns. Simple sugars are digested rapidly e.g. candy, juice. Starches take longer due to their complex make-up and provide a slow release of energy e.g. potatoes, wholegrain bread. Dietary fibre is found in all plant-based foods. It cannot be completely broken down and therefore is eliminated from the body without providing any energy (calories). 

The Different Types of Sugar

It is true that not all carbohydrates are created equally. Understanding how they are broken down is key to understanding their benefits. Processing of grains (e.g. wheat) removes parts that contain dietary fibre, antioxidants and B vitamins. This changes the nutrition profile of the food. For example, processing wheat is the difference between wholegrain and white bread. One slice of white bread contains 85 kcal, 17g carbohydrate and 1g fibre. One slice of wholegrain bread contains 90 kcal, 16g carbohydrate and 2g fibre. You might be wondering “well then… what is the difference between white and brown bread”?

  1. Wholegrain bread provides double the fibre content
  2. Wholegrain bread contains coarser* flour texture

*Coarse flour with higher fibre content results in slower release of sugar into the bloodstream and a more stable release of energy compared to white (refined) flour. 

Fuelling The Right Sugar

Regardless of its form, sugar is the preferred energy source for all human cells including the brain and skeletal muscles. Sugar is used up quickly especially during intense exercise. When excess sugar is available, muscle and liver cells can store it for energy in times of need. Having the ability to match carbohydrate needs (amount, timing and form) to daily intake helps you use carbs to your advantage. A good rule-of-thumb for sugar intake is to: prioritise starches and fibre and keep simple sugars to a minimum.

The glycaemic index (GI) categorises carbohydrates into 2 groups: low GI and high GI based on how they influence blood sugar levels over time. Higher fibre and fat content, carbohydrate form and grain processing affect GI. Use the GI of foods (see Figure 1) to identify those foods that provide energy quickly (e.g. pre-workout snack with toast and jam) or more slowly (e.g. pre-bed with skim milk and berries).

Fibre, fibre good for your heart…

Dietary fibre is not digested or absorbed in the human gut but has an important role in healthy bowel function and gut health (woohoo!). It also increases levels of satiety meaning you feel fuller for longer after eating a high-fibre meal. Fibre lowers the GI of foods, delays absorption of sugar into the blood and stabilises blood sugar levels. Fibre acts as food for ‘good’ bacteria of the gut which may reduce risk of chronic diseases including colon cancer, diabetes and heart disease. When gut bacteria feed on fibre, they produce compounds which reduce total and LDL-cholesterol reducing risk of cardiovascular disease complications e.g. stroke and heart attack. Plant-based foods are high in fibre including wholegrains, oats, legumes, nuts, seeds, fruit and vegetables (with skin intact). Higher fibre intake is linked to weight loss and reduced blood pressure. Optimal fibre intake is 25g per day (female) and 38g per day (male).

What does 25-35g fibre look like?  

  • 2-4 slices whole wheat bread
  • ½ avocado
  • ½-1 cup oat meal
  • ½ cup berries
  • 2 cups salad greens
  • 1-2 apple, pear or banana
  • 1 cup brown rice or soba noodles

Does sugar actually cause make us sick? 

So… fibre reduces risk of illness, but can sugar cause illness? The short answer is probably. Eating more sugar than we need has been associated with risk of obesity, diabetes and high cholesterol. I know… it’s confusing! How can something so necessary make us sick? The pathways are complex and researchers have not yet drawn conclusions on the direct impact of sugar on disease. There are many factors to consider such as exercise, calorie intake, genetics and body composition. It is likely that the type of sugar (fibrous or simple) in our diets has an impact on diabetes risk (read here). 

There are many new interesting discoveries surrounding the impact of our diet, including sugar, on our individual gut microbiomes (the second brain). The diet-gut relationship has been well studied with respect to sugar, although there is still much to learn! Types of sugar and sugar-alternatives affect the population of gut bacteria. Feeding ‘good’ bacteria helps prevent disease but in contrast, feeding ‘bad’ bacteria can perpetuate inflammation associated with inflammatory bowel disease. The question still remains, “Do all simple sugars feed the good, bad or any bacteria?”. 

Does Fruit Count as Sugar?

If you were thinking well, fruit is technically a simple sugar… you would be right! Whole fruits are composed of simple sugars and fibres. Juicing fruit removes fibre, leaving behind simple sugars. 1 glass of fruit juice contains up to 10g sugar, spiking blood sugar quickly. Whilst this can be useful before exercise, simple sugars should be kept to a minimum throughout the day. One bottle of VitHit is composed of less than 6% fruit juice concentrate providing only 10-35kcal and less than 6g of sugar. This small amount of juice does not provide enough sugar to cause a large spike in blood sugar.

This Food Safety Authority of Ireland (FSAI) categorisation of ‘low sugar’ products fits the bill for every bottle of VitHit (still and sparkling). Each bottle of VITHIT supplies less than 6g of sugar per 330ml. Therefore, total sugar and calories in VITHIT are low, making it a great option for anytime, day or night. 

Boost in particular is a great choice as it only has less than 2.5grams of sugar per bottle! 

Glycaemic Index of Common Foods

High GI Foods

  • White bread and pasta
  • Tortilla (wheat and corn)
  • White rice
  • French fries or baked potato 
  • Noodles
  • Couscous
  • Refined breakfast cereal

Medium-low GI foods 

  • Brown rice
  • Oatmeal
  • Whole-grain bread and pasta
  • Fruits (with skin)
  • Legumes
  • Low-fat dairy
  • Carrots

Sweet tips 

  1. Carb intake can be optimised to support balanced energy, enhanced mood and productivity
  2. Sugar, when eaten in the right amount, at the right time, in the right form (relative to individual needs), is healthy and necessary for health
  3. The source of sugar matters (less high GI foods, more low GI foods) 
  4. High-fibre foods (e.g. wholegrains, legumes, whole fruit & veg) balance blood sugar response and promote healthy gut microbiome 
  5. Eating a complex meal (carbohydrate, protein and fat) is super for prolonging energy and feeling your best after eating
  6. Get familiar with reading food labels to find the amount and type of sugar in foods (remember to check portion sizes) 
  7. Low sugar items contain less than 5g sugar per 100g (solid) and 2.5g sugar per 100ml (liquid)


Ciara McNulty
CORU Registered Dietitian DI047525

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