Health of the Nation: The hidden risks of diet bars and shakes exposed

They are often seen as a healthy snack and a quick way to lose weight, but a new study has found many protein bars and weight loss shakes have misleading nutrition details.

If you are trying to lose weight or pack in more protein by using health bars, diet shakes and sports foods you might be consuming more calories than claimed on the label.

And, you will be eating ultra-processed foods that could mess with your gut bacteria and undermine your mental and general health, experts have warned.

A recent study by Deakin University researcher Celeste Chapple looked at over 558 sports food products sold in Australian supermarkets, pharmacies, health food stores and gyms and found a third had incorrect nutrition information.

More than half the products with incorrect information understated the calorie count, the study found.

Deakin University researcher Celeste Chapple found sports food products, including protein shakes, bars and powders, don’t have the correct nutrition on the pack. Picture: Ian Currie

Protein bars in particular provided nutrient information that did not match the stated energy content on the nutrition panel, the study published in the journal Frontiers in Nutrition found.

“In addition to misleading nutrient information, almost all the sports foods surveyed included an artificial sweetener and many products contained multiple artificial sweeteners which we know can be harmful for some people,” Ms Chapple said.

“When you look at the ingredients list of a protein bar, there’s, a range of different things in there – additives, flavours. It’s an ultra processed food,” she said.

If you’re using these bars to get more protein for sport or weight loss it's better to start with real food, Ms Chapple said.

“Chickpeas, legumes have good sources of protein in them. Meat obviously. Milk yoghurt, cheese,” she said.

The hidden dangers of protein bars have been revealed.

Sales of sports foods in Australia have soared by 195 per cent since 2011 with protein bars the most popular and they are readily available in mainstream stores.

A 2021 UK study found extremely low calorie diet shakes were superior to a GP led weight loss program in delivering short term weight loss.

However, Dr Melissa Lane from the Deakin University Food and Mood Centre has found diet shakes and bars can alter a person’s gut bacteria.

And, she warns even though they are low in calories, they are ultra-processed foods.

People who consumed these products in a yoyo fashion over time may be negatively impacting their gut health “and that it’s linked with other things like inflammation and mental health might be impacted negatively. I suppose that’s the importance of it,” she said.

Multiple studies have raised health concerns about high fat, high salt ultra-processed foods which also contain ingredients like emulsifiers, foams, thickening agents, preservatives, and stabilisers and artificial sweeteners.

They have been linked to a higher risk of cardiovascular disease and death, obesity, high blood pressure, high cholesterol, type 2 diabetes and some cancers.

Deakin University researcher Dr Melissa Lane has found diet shakes alter your gut bacteria. Picture: Supplied.

Dr Lane said that despite the diet shakes and bars meeting all nutritional requirements and coming in at “around 800 to 900 calories a day” there are concerns.

“They meet all essential nutritional requirements in terms of micronutrients, like vitamins and minerals. And obviously, they’re very low in calories. So it’s definitely not your typical ultra-processed food,” Dr Lane said.

She’s now investigating this risk more deeply in a new study which compares two groups of people – one on a very low calorie healthy whole food diet and another group who lose weight using the diet shakes and bars.

“We know that they’re safe for human physiology, but in terms of our gut microbes, we didn’t really know what they were doing,” Dr Lane said.

“I think it’s probably assumed that because they meet all nutritional requirements, and they’re full of vitamins and minerals, and they’re low in calories and have adequate amount of protein and also fibre and micronutrients there was an assumption that they would act very similarly to a comparative diet that was based on whole foods.”

Her other research has found people who eat an ultra-processed diet are at greater risk of depression.

Originally published as Health of the Nation: The hidden risks of diet bars and shakes exposed