Geriatricians challenge view of insulin resistance in ageing as focus shifts to muscle, fat and brain health

Two European geriatricians argue that insulin resistance in older adults is more about declining physiological resilience in muscle, fat tissue, and the brain than just excess body fat, highlighting the importance of functional health over blood sugar metrics.

Two European geriatricians are arguing that insulin resistance in later life has been misunderstood for years: not simply as a by-product of excess body fat, but as a wider sign that the ageing body is losing reserve in muscle, fat tissue and the brain. Their paper, summarised in the source material, suggests that in older adults, chasing blood sugar alone may miss the larger decline in physical and metabolic resilience.

That view fits with long-standing research. The NCBI Bookshelf review on insulin resistance describes age, physical inactivity, visceral fat and nutritional imbalance as key drivers, while older studies in PubMed found that elderly people had higher glucose and insulin levels during glucose tolerance testing, consistent with insulin-resistant metabolism. Other research has linked fat distribution in older adults to impaired glucose handling, especially when visceral fat accumulates around the abdomen.

The geriatricians’ argument is that ageing muscle and fat behave differently from younger tissue. Muscle can lose metabolic efficiency before it visibly shrinks, meaning older people may handle glucose poorly even when body mass looks unremarkable. Fat tissue, meanwhile, can become more inflammatory with age and lose its ability to store energy safely, pushing fat into the liver and muscle where it interferes with insulin action. A separate study on metabolic flexibility in older adults found that reduced ability to switch fuels during exercise was associated with glucose intolerance, reinforcing the idea that this is about declining physiological adaptability, not just weight.

The paper also extends the case to the brain. Age-related insulin resistance in neural tissue has been associated with poorer glucose uptake, weaker synaptic function, memory problems and late-life depression. On that basis, the authors argue that treatment should be judged not only by glucose numbers but by whether it preserves strength, mobility and cognition. The source material points to resistance training as one practical lever: in adults over 60, it improved insulin resistance and long-term blood sugar control, while structured exercise and nutrition programmes improved physical performance in frail older diabetics. The larger message is that, in later life, metabolic care may need to focus less on a dashboard warning light and more on the engine itself.