Obesity has been linked to faster brain aging, but can losing weight turn back the clock?
A new study provides compelling evidence that shedding pounds through lifestyle changes may attenuate brain aging.
Key facts:
- Participants lost an average of 5% of body weight after 18 months of diet and exercise
- Just 1% weight loss corresponded to 8.9 months reversal in brain aging
- Changes in liver health and fat deposits were tied to slower brain aging
- Eating less processed foods, sweets and sugary drinks also linked to brain benefits
- The findings demonstrate that obesity-driven brain aging may not be irreversible with weight loss interventions.
Source: eLife. 2023; 12: e83604.
Brain Aging Linked to Obesity
Prior studies have shown obesity corresponds to faster brain aging compared to lean individuals of the same chronological age.
Researchers can estimate “brain age” based on detailed brain scans. If a 45-year old’s brain looks 50 years old, their “brain age” is considered advanced.
This accelerated aging manifests in reduced brain volumes and altered connectivity patterns similar to normal aging.
Cognitive impairment and dementia risks also rise with midlife obesity.
Experts theorize biological aging is accelerated by obesity-related factors like:
- Chronic inflammation
- Metabolic dysfunction
- Vascular damage
- Oxidative stress
Can Weight Loss Slow Brain Aging?
While the negative effects of obesity are clear, it has been unclear if losing weight can reverse brain aging.
A new study published in eLife is the first to demonstrate obesity-associated brain aging may be attenuated with successful weight loss intervention in humans.
The researchers had 102 middle-aged obese adults follow an 18-month diet and exercise program. They measured brain scans and biomarkers before and after.
Participants lost about 2.3 kg (5 pounds) on average. But even this modest 5% weight loss corresponded to nearly a year reversal in brain aging.
Small Weight Loss = Big Brain Boost
The exciting finding was that just 1% weight loss related to 8.9 months reversal in brain aging!
This was measured by comparing participants’ chronological age to brain age estimated from MRI scans.
Those who lost the most weight showed brains that looked younger relative to their age after 18 months.
While the average weight loss was small, the brain aging results were dramatic.
This suggests obesity-related brain decline may be fairly reversible with lifestyle changes.
Brain Boost Tied to Liver Health
The researchers also tracked measurements like liver fat, blood biomarkers, and fat deposits.
Improvements in certain liver health markers were tied to slower brain aging.
Participants with decreased liver fat and enzymes after weight loss showed attenuation in brain aging.
The liver relevance is not surprising since liver disease is also tied to worse neurological health.
Losing weight likely corrected obesity-related metabolic dysfunction that was harming the brain.
Less Processed Food = Younger Brain
Participants completed detailed diet questionnaires before and after intervention.
Reduced consumption of heavily processed foods was linked to greater reversal in brain aging.
Eating less sweets and sugary beverages was also associated with benefits.
This highlights nutrition quality, not just weight loss, could be important for brain health.
The Big Picture
This well-designed study provides strong evidence that brain aging acceleration in obesity can be reversed through lifestyle interventions like:
- Modest weight loss (~5% body weight)
- Exercise
- Improvements in liver health
- Limiting processed foods
- While the participants were obese, similar benefits may apply to overweight individuals.
The findings are encouraging since global obesity rates continue rising.
Modest weight loss through diet and activity modifications seem attainable for many people compared to intensive interventions like surgery.
Limitations and Future Directions
Some limitations were the study included mostly men, and a control group was lacking.
But results clearly linked weight loss to improved brain health biomarkers.
Future studies should examine whether reducing brain aging biomarkers ultimately equates to better cognitive outcomes.
Following participants long-term could confirm lasting cognitive benefits.
Researchers also want to test anti-aging diets and multimodal programs that optimize nutrition, activity, sleep and stress management.
Combination approaches may maximize brain benefits.
Conclusion
This study provides compelling evidence that obesity-related brain aging is not irreversible.
Losing just a few pounds through improved nutrition and added activity could help reverse brain aging by nearly a decade.
Managing weight and metabolism earlier in life may be key to maintaining a younger brain long-term.
References
- Study: The effect of weight loss following 18 months of lifestyle intervention on brain age assessed with resting-state functional connectivity
- Authors: Gidon Levakov et al. (2023)
