Cells need energy and nutrients to work.
They must constantly decide what to do with the fuel available to them. After a meal, the body may store energy and support growth. Between meals or during exercise, cells may use stored energy and focus more on maintenance and repair.
This ability to recognise how much energy and food are available is called nutrient sensing.
It is controlled by signals that tell cells whether to grow, store energy, use fuel or carry out repairs. Insulin is one of the better-known signals involved in this process.
As we age, cells may become less accurate in reading and responding to these signals. Scientists call this deregulated nutrient sensing.
The term sounds complicated, but the basic idea is simple: the body becomes less flexible in the way it handles food and energy.
A healthy system should respond differently after eating, during activity, while resting and during recovery. It should be able to move between storing energy and using it.
With age, this balance may become harder to maintain. Cells may respond less effectively to glucose and other nutrients. The body may also remain in a “storage and growth” mode when repair and maintenance would be more useful.
This does not mean that food causes ageing or that eating as little as possible is the answer.
The goal is balance, not deprivation.
Eating too little can lead to loss of muscle, weaker bones, nutritional deficiencies and slower recovery, especially in older adults.
Eating too much over a long period can also make it harder for the body to control blood glucose, body weight and energy use.
Regular physical activity helps muscles use glucose and improves the body’s ability to respond to changing energy needs. Adequate protein supports muscle maintenance, while a balanced diet helps provide enough energy without constant excess.
Nutrient sensing is connected with other changes that happen during ageing.
Poor metabolic control can increase stress inside cells, affect energy production and contribute to inflammation. Loss of muscle and physical inactivity can make this balance even more difficult.
There is no single test that shows how well every nutrient-sensing system is working.
In everyday medicine, practical measures such as blood glucose, blood pressure, cholesterol, body composition and physical fitness are more useful.
Healthy ageing does not require constant fasting or constant restriction.
It depends partly on the body’s ability to use food and energy in the right way as its needs change.
