One of the factors that increases the risk of acquiring type 2 diabetes is excess body fat. So it makes sense that losing weight has always been one of the first lines of defense against the disease. Yet people who are slender -skinny, even- sometimes develop type 2. Why is that? Does the fact that a slender person can acquire type 2 negate the need for weight control?
It turns out there is an explanation for this seeming contradiction: sarcopenia, a condition of low muscle mass and strength that actually increases insulin resistance. Derived from the Greek words meaning “poverty of flesh,” sarcopenia is an affliction commonly associated with the elderly. As people grow old, their muscle mass and tone declines. Because muscles are the body’s greatest “consumers” of blood glucose, they are crucial to the maintenance of proper blood sugar levels.
Young and middle-aged people can have sarcopenia, too. Lack of muscle mass is also common in obese individuals. Despite their large size, their muscles have become weakened by sedentary habits brought on by the difficulty of moving comfortably with great weight.
The role of sarcopenia in the onset of type 2 was elucidated by recent research at the University of California Los Angeles. Researchers there did a cross-sectional analysis of data on 14,528 people who had been tracked by the National Health and Nutrition Examination Survey III -an exhaustive cross-relational database that has allowed researchers to find previously unsuspected relationships among diseases and disease-causing factors.
The UCLA researchers found that sarcopenia was associated with insulin resistance in people whether they were obese or not. Because insulin resistance is considered a prime factor in the development of type 2, the researchers also searched for other diabetes-related factors that were associated with sarcopenia. They found that in the elderly, the condition was associated with higher blood sugar levels in obese people, but not in thin. In people under the age of 60, both obese and thin people who had sarcopenia also had higher blood sugar levels.
Nobody knows if there is a chicken-or-egg chain of causation here. Does low muscle mass, for whatever reason, invite the onset of insulin resistance and, later, type 2? Or does some factor that is also associated with diabetes create sarcopenia, thus starting a cascade of events that pulls an individual toward type 2?
Whatever the answer, one response to sarcopenia appears to be old-fashioned resistance training, involving exercises with weights designed to increase muscle tone and mass. In that case, putting on weight is not a drawback because the extra pounds are glucose-consuming muscles, not insulin-resistant fat.
A summary of the study is available here.
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