It has been emphasised during the pandemic that shifting excess pounds can reduce the risk a coronavirus infection will prove fatal for those of all age groups.
But new research has found that carrying too much weight in your younger years could contribute to faster mental decline in later life.
The study, published in the medical journal Neurology, has linked being obese in your twenties and thirties and problems with basic thinking and memory skills in older age.
Having high blood pressure or high glucose levels has also been found to cause similar future issues.
It is thought that being overweight triggers inflammation, which can negatively impact on blood flow to the brain and increase stiffness in arteries.
According to The Sunday Times, study leader Dr Kristine Yaffe, of the University of California, said: "These results are striking and suggest that early adulthood may be a critical time for the relationship between these health issues and late-life cognitive skills."
For the findings, the researchers looked at 15,000 people aged 18 to 95 – tracking their body mass index (BMI), blood glucose levels, blood pressure and cholesterol for up to 30 years.
Having a high BMI, blood pressure and glucose levels doubled the average rate of cognitive decline, while being obese – which means having a BMI over 30 – doubled this deterioration on its own.
Through this analysis, the scientists discovered that being overweight in your twenties and thirties is worse for brain health than carrying excess weight in middle or old age.
Currently, according to an NHS survey from 2019, almost a quarter, or 23%, of adults in the UK between the ages of 24 and 34 are obese – and it's thought obesity affects a total of almost four million young people.
It comes after health professors previously urged that getting fit and shifting excess pounds by doing home workouts or getting outside for a walk, cycle or run once a day could save your life.
Experts have warned that a coronavirus infection may prove fatal for those who are unfit or obese.
Last April, according to the NHS, the 38% of people admitted to intensive care for conditions related to COVID-19 were obese – and of that group 55% died.