Weight Changes Before Dementia Diagnosis
Many people notice shifts in body weight years before a dementia diagnosis. These changes can signal early brain problems, but they work in different ways depending on a person’s starting weight and gender.
Researchers have found that people who are obese at the start of a study often have lower levels of certain blood proteins linked to Alzheimer’s disease, like p-tau217 and neurofilament light chain, or NfL. These proteins show neuron damage and amyloid buildup in the brain. At first glance, obesity seems protective. But over time, the story changes. Obese individuals see much faster rises in these proteins, with p-tau217 jumping 29 to 95 percent quicker and NfL 24 percent faster. Amyloid on brain scans also builds up 3.7 percent faster in this group.[1][3]
This speed-up suggests obesity hastens Alzheimer’s changes, even if baseline tests look better. Experts warn that just checking weight once can miss the full picture, as weight loss from early disease might skew results. Tracking weight over years gives a clearer view of risk.[1][3]
On the other hand, unexplained weight loss often appears before diagnosis, especially in women. Studies show women lose more body mass than men in the years leading up to dementia. This drop can happen without trying, due to forgetting to eat, losing interest in food, or trouble with appetite. In advanced stages, swallowing issues add to the problem, making weight loss common.[2][4]
Gender plays a role here. Weight loss stands out as an early clue in women, while men might not show it as much. Doctors note that spotting these appetite shifts early could help with detection.[2]
Depression ties in too. Certain midlife mood symptoms, like loss of confidence or trouble coping, raise dementia risk by up to 50 percent decades later. These can lead to poor eating habits and weight changes.[5][6]
Keeping a steady weight through life might lower risks. Blood tests catch these shifts faster than brain scans, pointing to the value of regular checks.[3]
Sources
https://www.medicalnewstoday.com/articles/obesity-may-hasten-alzheimers-disease-development
https://int.livhospital.com/cognitive-decline-symptoms-best-list/
https://www.sciencedaily.com/releases/2025/12/251210092019.htm
https://myhometouch.com/articles/the-effects-of-alzheimers-on-the-body
https://www.news-medical.net/news/20251215/Six-midlife-depressive-symptoms-linked-to-dementia-decades-later.aspx
https://www.alzinfo.org/articles/diagnosis/6-symptoms-of-depression-that-may-raise-your-alzheimers-risk/
https://www.sunriseseniorliving.com/resources/dementia-and-memory-care/is-it-time-for-memory-care
