Social and environmental cues, like the sight of other animals eating or the scent of a tasty meal, can trigger overeating in animals – even when they’re not hungry.
These cues can also override rational decision-making in humans, leading to the over-consumption of high-calorie, nutrient-poor foods, which contribute to obesity and related health issues such as heart disease and cancer.
A recent study led by from the University of Technology Sydney reviews the evolution of research into these cues to identify the behavioural patterns, brain pathways, and chemical systems responsible for this effect.
The study, ‘ ,’ co-authored with Associate Professor Laura Corbit from the University of Toronto, was recently published in the journal Neurobiology of Learning and Memory.
“It’s important to understand the environmental cues that lead us to eat and how they influence our food choices so we can develop better strategies to prevent overeating and encourage healthy eating habits,” said Dr Kendig.
“The festive season is filled with cues that encourage eating – Christmas celebrations, social gatherings, and an abundance of indulgent foods – and it can be easy to overindulge and eat more than intended,” he said.
The researchers reviewed a wide range of studies, from early behavioural approaches to more recent studies that use pharmacological and neural techniques, to examine cues that trigger overeating.
Some of the cues and behaviours highlighted include the finding that sated animals will resume eating when a hungry companion joins them, and that environments with many food choices are more likely to trigger overeating.
Animals will also eat new foods more readily in the presence of another animal eating nearby, even if the animal is from a different species. For example, group housing typically increases feeding rates in pigs and cows.There’s growing interest in how external cues influence food intake, especially as the sharp rise in global obesity suggests that environmental factors, rather than genetics, are driving the trend.
Social hierarchies within groups may also influence food consumption, with dominant pigs consuming more food than others. Eating also offers the opportunity to establish social hierarchies. Chickens have a strong pecking order, with more dominant birds eating first.
“There’s growing interest in how external cues influence food intake, especially as the sharp rise in global obesity suggests that environmental factors, rather than genetics, are driving the trend,” said Dr Kendig.
The term “obesogenic environment” is used to describe how factors such as advances in technology and food manufacturing can encourage overeating and discourage physical activity.
While the effects of cues in animal research may seem subtle and influenced by specific experimental conditions, similar behaviours have been observed in humans.
Even small, repeated energy surpluses can eventually lead to weight gain, meaning these minor effects should not be dismissed as insignificant. By identifying these factors, the researchers hope to curb overconsumption and encourage healthier eating habits.