Obesity has been linked to an increased risk of developing dementia later in life, according to numerous studies. Dementia charities emphasize the importance of maintaining a healthy weight to promote brain health, but some research suggests that obesity may actually have a protective effect against dementia.

The relationship between obesity and dementia is complex and not fully understood. Conducting a randomized trial to determine the effects of obesity on dementia risk would be unethical, as most research relies on observational studies that follow large groups of people over time. Two common concerns in these studies are “reverse causation” and “confounding bias.” Reverse causation occurs when early signs of dementia cause weight loss, not the other way around. Confounding bias arises when a third factor related to both obesity and dementia could be influencing the observed relationship.

A recent study has suggested that lower childhood intelligence may be a factor that influences both obesity and cognitive decline in middle-aged adults. This highlights the complexity of understanding the link between obesity and dementia, as it may involve multiple interconnected factors. Further research is needed to unravel the complexities of this connection. Maintaining a healthy weight is still vital for overall health, but more information is needed to fully understand how it affects cognitive decline and dementia risk.