Excess calories during development may alter the brain and spur adult overeating
by Rutgers University
FAB RESEARCH COMMENT:
This animal study confirms previous research showing that:1) unlimited access to a high-fat, high-sugar diet (i.e. a typical western-type diet, rich in ultra-processed foods) promotes overeating and obesity
- but very importantly:
2) children born to mothers with diet-induced obesity in pregnancy have increased risks for overeating and obesity themselves
- unlimited access to healthy food does NOT have this effect.
Again very importantly, however, this study found that these increased risks of obesity in the offspring only occurred when there was unlimited access to an unhealthy, high-fat and high-sugar diet, i.e:
- children of obese mothers did NOT overeat and become obese themselves when given unlimited access ONLY to a healthy diet (i.e. low in added sugar, and with a similarly healthier fat content, as found in whole or minimally processed foods).
By contrast, all the offspring ate more when given access to highly palatable, sugary and fatty foods or drinks, but this effect was significantly greater in those from mothers with diet-induced obesity - who then became obese themselves.
The researchers were also able to pinpoint some of the likely mechanisms underying this early 'nutritonal programming' effect on the developing brain, as they found that maternal overnutrition during pregnancy and breastfeeding led to differences in the connectivity between different brain regions known to be important for memory and emotional processing.
These findings show that diet-induced obesity in the mother actually 'primes' the developing brain of her children
- if they eat sugary, fatty foods at all, they will find it much more difficult to resist overeating these supposed 'treats' than the children of normal weight mothers.
These findings strongly indicate that for the children of obese mothers, their supposed 'lack of willpower' - i.e. being unable to resist overeating when surrounded by unhealthy junk foods - may in fact be a 'hardwired' consequence of their own mothers' diet-induced obesity during pregnancy and breastfeeding.
The more encouraging implication of the findings is that
- IF such children could avoid high-sugar, high-fat foods and eat a healthy diet instead, then they are NOT pre-destined to become obese themselves (even though their mother was).
Clearly, the current unhealthy food environment that most human children are exposed to makes this quite difficult - but raising awareness and improving knowledge of these damaging intergenerational effects of diet would be a start.
What is really needed to address 'the obesity crisis', however (and always has been) is effective goverment action to deter consumption of ultra-processed high-sugar, high-fat foods, and ensure that healthy and nutritious food is affordable and available to all. STUDY LIMITATIONS - and OTHER EVIDENCE
Obviously as this was an animal study, its generalisability to humans can always be questioned by those who still wish to deny the ever-increasing evidence linking diets rich in high-sugar, high-fat ultra-processed foods and drinks to the current epidemic of obesity and chronic disease.
However, in addition to a highly consistent picture from human association studies, recent converging evidence includes:
- a unique long-term human population study indicating powerful 'nutritional programming' effects, in which higher maternal sugar consumption in pregnancy and early life led to 2-3 times higher rates of chronic disease in their children 50 years' later. See:
- human randomised controlled trial evidence that unlimited access to ultra-processed foods vs a whole or minimally processed diet causes significant but 'unconscious' overeating in healthy adults - and a weight gain of almost 1kg in just 2 weeks.
For details of the underlying research, see:
For further information please see:
20/03/2023 - Medical Xpress
People whose mothers are overweight during pregnancy and nursing may become obese as adults because early overnutrition rewires developing brains to crave unhealthy food, according to a Rutgers study in Molecular Metabolism.
Rutgers researchers traced this link from mother to child in mice with an experiment that began by letting some mice get obese on unlimited high-fat food during pregnancy and breastfeeding while keeping others slim on limitless healthy food.
They found that mice born to obese mothers stay slim in adulthood on unlimited healthy food but overeat more than mice born to lean mothers when given access to unhealthy food.
The findings indicate that while people whose mothers were overweight during pregnancy and nursing may struggle to moderate their consumption of treats, they could safely eat their fill of healthy foods.
The study may also help inform the development of brain-altering drugs that reduce cravings for unhealthy food.
"People born to overweight or obese mothers tend to be heavier in adulthood than people born to leaner mothers, and experiments like this suggest that the explanation goes beyond environmental factors such as learning unhealthy eating habits in childhood," said Mark Rossi, a professor of psychiatry at Rutgers Robert Wood Johnson Medical School and senior author of the study.
"Overnutrition during pregnancy and nursing appears to rewire the brains of developing children and, possibly, future generations."
In the experiment, researchers gave the high-fat food to three sister mice and the healthy chow to another three of their sisters. Once breastfeeding was complete, the researchers turned their attention to the nearly 50 pups—who predictably started at heavier or lighter weights, depending on their mom's diet.
Their weights converged (at healthy levels) after all the pups received several weeks of unlimited healthy chow, but they diverged again when the researchers offered them constant access to the high-fat diet.
All the mice overate, but the offspring of overweight mothers overate significantly more than the others.
Further analysis indicated that the differing behaviors probably stemmed from differing connections between two parts of the brain—the hypothalamus and the amygdala—that arose because of differing maternal nutrition during pregnancy and breastfeeding.
The study has mixed implications for people born to overweight mothers who struggle with their own weight. On the one hand, it suggests the possibility of staying lean while eating healthy food to satiety and avoiding junk entirely. On the other hand, it suggests that efforts to eat moderate quantities of unhealthy treats may spur overconsumption and obesity.
Looking forward, the study's finding about disrupted brain circuits in the two groups of mice may help inform the creation of drugs that would block the excess desire to consume unhealthy foods.
"There's still more work to do because we don't yet fully understand how these changes are happening, even in mice," Rossi said. "But each experiment tells us a little more, and each little bit we learn about the processes that drive overeating may uncover a strategy for potential therapies."