What I learned when I gave up sugar for six weeks - BBC

While I typically eat a healthy diet with plenty of home-cooking, I also have a sweet tooth and tend to consume a chocolate treat or two every day.

That's not very surprising – overconsumption of sugar is extremely common in our modern diets. It's bad for our teeth, harmful to our health and there is even some evidence to suggest eating too much sugar might lead to long-term cognitive deficits.

As my role involves reporting on health and wellbeing, I've increasingly started to worry about eating so many treats, which alongside refined sugar, often contain numerous additives. In fact, one of my regular treats contains more than half my daily recommended amount of sugar.

Dietary guidelines in the US recommend consuming fewer than 12 teaspoons of added sugar from food and beverages (around 50g) while in the UK, the NHS recommends people eat less than seven teaspoons (30g) of sugars per day. In reality US adults eat more than 16-17 teaspoons (65-70g) a day, according to the US National Health and Nutrition Examination Survey. To put that in context, 4g is about one level teaspoon of sugar.

Giving up all that sugar isn't easy either. But I decided to see if it was indeed possible to break out of my daily sugar habit.

I set myself the challenge of not eating any foods containing added refined sugar for six weeks. I also avoided honey and fruit juice but I continued to eat natural sugars found in whole fruit, as well as complex carbohydrates – which when eaten, our body breaks down into the sugar glucose which provides our body and brain with its main source of energy.

From the outset, I noticed some surprising changes to my energy levels and how I felt. The post-lunch slump went away but I did often find myself listlessly looking in my fridge trying in vain to find something interesting (sweet) to munch on, feeling as though I was missing out.

First, it's worth reflecting on just how much sugar is added to our food. I found it surprisingly hard to avoid. Browsing my local supermarket shelves, I noticed it in food I didn't expect, including a deli sourdough sandwich, which contained 5.7g of sugar and a bolognese ready meal (9g). Many breakfast cereals include added sugars and a slice of commonly bought supermarket bread had about 1.2g of sugar per slice.

Sugar is also abundant in many ultra-processed foods – which have known adverse health outcomes and tend to contain fewer nutrients than whole foods like fruits, vegetables and whole grains.

There are many different forms of sugar in our foods. Glucose is perhaps the most common, but you can also find fructose in fruits and many syrups, lactose in milk and sucrose, which is commonly known as table sugar and is one of the main forms of added "free sugar" in our diets. Free sugars area also found in juices, syrups and honey as they are not bound up in the cells of our food. These refined free sugars contribute most to adverse health effects.

"We come out of the womb liking sweet tastes, it's part of mother's milk in those early days where you're supposed to be gaining a lot of weight," says Ashley Gearhardt, a professor of psychology at the University of Michigan. The problem, she says, is that "we've gotten so good at delivering sweetness really cheaply".

Research shows that when we consume high-sugar foods it rapidly increases our blood sugar levels. While that's a normal process after eating, if they happen too often we can become resistant to insulin, and the risk of developing type 2 diabetes increases. High-sugar diets are also linked to cavities, inflammation, obesity, Alzheimer's disease and cancer.

"Diet related diseases like diabetes are now killing people beyond the scope of alcohol and opiates and [unhealthy food] is competing with tobacco for being the most deadly substance in the world," says Gearhardt.

For instance, sugar has been found to increase fat in the liver. In one randomised controlled trial, those who consumed high-sugar drinks for several weeks showed about double the amount of fat in their liver, even if they consumed the same calories overall.