Cheeky diet soda helps you get through the workday? This is what it means for your health

By Lauren Ball and Emily Burch for ‘The Conversation’

Queensland: Many people are drinking less sugary soft drinks than they used to. This is a major victory for public health, given the recognised risks of diets high in sugary drinks.

But over time, the consumption of diet sodas has increased to the point where they are now regularly found in wastewater.

So what does the research say about how drinking them often will affect your long-term health? What makes diet sodas sweet? The World Health Organization (WHO) advises people to “reduce their daily intake of free sugars to less than 10 percent of total energy intake. A further reduction to less than 5 percent, or about 25 grams (six teaspoons) per day, would provide additional health benefits.” But most regular sodas are high in sugar. A 12-ounce can of original Coca-Cola contains at least seven teaspoons of added sugar.

Diet sodas are designed to taste like regular sodas, but without the sugar. Instead of sugar, diet sodas contain artificial or natural sweeteners. The artificial sweeteners include aspartame, saccharin, and sucralose. The natural sweeteners include stevia and monk fruit extract, which are derived from plant sources.

Many artificial sweeteners are much sweeter than sugar, so less is needed to experience the same sweetness.

Diet soft drinks are marketed as healthier alternatives to regular soft drinks, especially for people who want to reduce their sugar intake or manage their weight.

Surveys of Australian adults and adolescents show that most people understand the benefits of reducing their sugar intake. However, they are often less aware of the potential effects of diet drinks on general health.

What does the research say about aspartame? The artificial sweeteners in soft drinks are considered safe for consumption by food authorities, including in the US and Australia. However, some researchers have raised concerns about the long-term risks of consumption.

People who regularly and frequently drink diet soft drinks have a higher risk of certain metabolic diseases (such as diabetes and heart disease) than people who do not drink diet soft drinks.

The association was also found after taking into account other dietary and lifestyle factors (such as physical activity).

In 2023, the WHO announced that reports had shown that aspartame – the main sweetener used in diet soft drinks – was “possibly carcinogenic to humans” (carcinogenic means cancer-causing).

Importantly, the report notes that there is currently insufficient scientific evidence to be absolutely certain that aspartame can increase the risk of cancer. It also stresses that it is safe to use occasionally.

Do diet sodas help with weight control? Despite the word “diet” in the name, diet sodas are not strongly linked to weight control.

In 2022, the WHO conducted a systematic review (where researchers looked at all available evidence on a topic) to investigate whether the use of artificial sweeteners is beneficial for weight management.

Overall, the randomized controlled trials they looked at suggested that there was slightly more weight loss in people using artificial sweeteners.

However, observational studies (where no intervention takes place and participants are followed for a longer period of time) have shown that people who consume large amounts of artificial sweeteners are more likely to have a higher BMI and are 76 percent more likely to be obese.

In other words, artificial sweeteners may not directly help with long-term weight management. This resulted in the WHO advising against using artificial sweeteners for weight management.

Animal studies have suggested that consuming high levels of artificial sweeteners can signal the brain that it is being starved of fuel, leading to more eating. However, evidence that this happens in humans is still unproven.

What about inflammation and dental problems? There is some early evidence that artificial sweeteners may irritate the lining of the digestive tract, which can cause inflammation and increase the likelihood of diarrhea, constipation, bloating and other symptoms often associated with irritable bowel syndrome. However, this study noted that more research is needed.

There has also been a link found between drinking large amounts of diet soda and liver disease, which is caused by inflammation.

The consumption of diet soft drinks has also been linked to tooth erosion.

Many soft drinks contain phosphoric acid and citric acid, which can damage the enamel of your teeth and contribute to tooth erosion.

Moderation is the secret As with many aspects of nutrition, when it comes to diet sodas, moderation is the secret.

Drinking diet soda occasionally is unlikely to harm your health, but frequent or excessive consumption may increase health risks in the long term.

Plain water, flavored water, sparkling water, herbal tea, or milk remain the best options for staying hydrated.

(Lauren Ball is Professor of Community Health and Wellbeing at the University of Queensland | Emily Burch is an Accredited Practising Dietitian and Lecturer at Southern Cross University)

Published July 20, 2024, 08:46 IST