We strongly associate being overweight with higher risk of type 2 diabetes. And it’s true that there is a strong link between the two. But it’s entirely possible to be develop diabetes when you’re at a healthy weight, or even when you’re underweight. A recent study carried out by researchers at the University of Florida may explain why up to 33% of slim adults living in the United States have pre-diabetes.
Hidden Metabolic Problems
Arch Mainous III is the lead author of the University of Florida study and chair of health services research, management, and policy in the College of Public Health and Health Professions. He said of his research, “A lot of people who we would consider to be at a healthy weight – they’re not overweight or obese—are not metabolically healthy.”
The Centers for Disease Control and Prevention reports that 29 million Americans are diabetic, and another 86 million are teetering on the edge of the disease with prediabetes. Prediabetes means blood sugar levels have escalated outside of normal range but aren’t high enough to warrant a type 2 diabetes diagnosis. However, those with prediabetes face a greatly increased risk for full-blown diabetes … heart disease … and stroke.
The Price of Inactivity
Mainous and his colleague examined data collected from over 1,000 people, all of whom were at a healthy weight and none of whom had a history of diabetes. Those who reported low levels of 
physical activity in their day to day lives were significantly more likely to have a blood sugar level of 5.7 or above, the cutoff identified by the American Diabetes Association for prediabetes.
Nearly 25% of all inactive people met the criteria for prediabetes. For those over age 45, that percentage rose to upward of 40%. “Our findings suggest that sedentary lifestyle is overlooked when we think in terms of healthy weight,” Mainous said. “We shouldn’t focus only on calorie intake, weight or [body mass index] at the expense of activity.”
Muscle to Fat Ratio Matters
The University of Florida study didn’t confirm a direct cause-and-effect relationship between inactivity and prediabetes, but the researchers believe the underlying cause may be that inactive people have a higher proportion of fat to lean muscle.
Because of the health problems associated with pre-diabetes, learning more about the origins of the condition is an essential step to overcoming the problem. The University of Florida study is an important reminder that health can’t be measured by the numbers on the scale.
