A person can look slim, maintain the same weight for years and still be losing something that plays a major role in controlling blood sugar: muscle. This change can happen gradually, especially with age, reduced physical activity or long periods of sitting. And its effects may go beyond weaker arms, slower walking or difficulty climbing stairs.

Muscles do much more than help the body move. They are also major users of glucose, the sugar circulating in the bloodstream. When muscle mass declines, the body may lose some of its capacity to clear glucose efficiently, potentially increasing the risk of insulin resistance and type 2 diabetes.

The connection is supported by research. A study published in Diabetes & Metabolism Journal followed middle-aged and older Korean adults for a median of 9.06 years. Among the participants, 1,336 developed type 2 diabetes. Researchers found that people in the lowest muscle-mass group had approximately twice the risk of developing diabetes compared with those in the highest group, even after accounting for factors such as body fat and waist circumference.

Another large study involving 203,767 adults found a similar pattern. Participants with the lowest relative muscle mass had a higher risk of developing type 2 diabetes than those with the highest muscle mass. The association was seen in both men and women.

Muscle tissue acts as a storage and utilisation site for glucose. After a meal, carbohydrates are broken down into glucose, which enters the bloodstream. Insulin helps move this glucose into cells, where it can be used for energy or stored for later.

Skeletal muscle accounts for around 80% of insulin-stimulated glucose disposal in the body. When muscle mass declines, the body may have less capacity to take up and use glucose. If the remaining muscle also becomes less responsive to insulin, blood sugar regulation can become more difficult.

Dr Jayanta Thakuria, Senior Director – Internal Medicine and Rheumatology at Yatharth Super Speciality Hospital, Faridabad, Sector 88, explains that muscle plays an important role in glucose uptake and insulin sensitivity.

"Without muscle mass, your body becomes less capable of utilizing glucose properly, which leads to a condition known as insulin resistance," he says.

Yes. Muscle loss can develop gradually, particularly with ageing, physical inactivity, prolonged illness or inadequate nutrition. A person may notice that everyday activities such as climbing stairs, carrying shopping bags or getting up from a chair are becoming harder. However, these changes are not always obvious, and body weight alone cannot tell you how much muscle you have.

This is also why being thin does not automatically mean having a healthy metabolic profile. Research has found an association between lower muscle mass and type 2 diabetes even among people who are not classified as obese.

Strength training is one of the most useful ways to preserve and build muscle. Exercises such as squats, resistance-band movements, weight training and modified push-ups can help improve muscle strength. Regular walking and other physical activities also support metabolic health, although they do not replace resistance training.

The American Diabetes Association's 2026 Standards of Care recommend that adults with diabetes undertake 150 minutes or more of moderate-to-vigorous physical activity each week, along with two to three resistance-training sessions on non-consecutive days.

Diet matters too. Adequate protein from foods such as eggs, dairy products, pulses, soy, fish and lean meat helps support muscle maintenance and repair. Dr Thakuria also emphasises the importance of sufficient protein intake alongside regular strength training and everyday movement.

Muscle loss does not automatically mean someone will develop diabetes. Genetics, age, body fat distribution, diet and other health factors also influence risk. But preserving muscle is more than a fitness goal. It is one way to support the body's ability to manage blood sugar as it ages.