They reckon virtue is its own reward – in fact it’s the only reward if you’ve been living the bitter dream of a low-carbohydrate diet and artificial sweeteners.
Together they make you fat. New research shows that some of our most vulnerable people – those who doggedly stick at a small tuna salad and a ‘low sugar’ soft drink for lunch – end up hungrier because of their diet, eat a lot more than they intended, and put on weight.
The study, published this week in Cell Metabolism, builds on previous research that found artificial sweeteners mimicked a starvation state in the brain, causing fruit flies and mice to seek energy by eating more food.
In other words, chronic consumption of artificial sweeteners made them hungry.
The new study − by the same team from the University of Sydney’s Charles Perkins Centre and School of Life and Environmental Sciences − also involved fruit flies that were fed varying amounts of carbohydrate and sweeteners, and the subsequent intake of food was then tracked.
Flies on a duet combo of artificial sweeteners and low carbohydrates diet showed ”an immediate increase” in food consumption.
Notably, the increase in consumption varied according to the dose of sweeteners provided and “was not observed in flies consuming unsweetened foods”, according to a statement from the university.
New findings not so sweet
The researchers have also raised questions on previous research that found consumption of an artificial sweetener alongside a higher carbohydrate diet actually suppressed food intake, and therefore seemed to help reduce calories consumed.
However when examined in detail, ”these results were not reproducible, and flies that were offered a higher carbohydrate diet and consumed higher doses of sweeteners did not simultaneously reduce their food intake”.
Lead researcher, Associate Professor Greg Neely from the University of Sydney’s Faculty of Science, said the new findings supported the team’s previous conclusions.
“Distorting the perceived energy value of food, by manipulating sweetness through artificial means, has unanticipated consequences in these animal studies,” he said.
Assoc Prof Neely also led the 2016 study with flies and mice that revealed chronic consumption of artificial sweeteners increase feelings of hunger due to a complex neuronal network that responds to artificially sweetened food by telling the animal it hasn’t eaten enough energy.
“Through systematic investigation of this effect, we found that inside the brain’s reward centres, sweet sensation is integrated with energy content. When sweetness versus energy is out of balance for a period of time, the brain recalibrates and increases total calories consumed,” Assoc Prof Neely said in a statement at the time.
Calls to Coca-Cola and Pepsi for comment were responded to with a statement from the Australian Beverages Council, which read: “It’s really important to note this most recent study was related to fruit flies, under experimental conditions.
“As such, the relevance of these results to real people consuming real foods and beverages in everyday real life, is very limited, at best. The authors themselves note the significant limitations of their findings.”
The statement continued: “Numerous meta-analysises have concluded that replacing sugar with non-nutritive or low-energy sweeteners results in less energy consumed and weight loss.
“Further, expert reviews conclude that the evidence for an effect on increasing appetite or ‘sweet tooth’ is absent or inconclusive.”
Watch this expanding space.