Fat distribution plays role in weight loss success for people at risk for diabetes

Machann J. Radiology. 2010;doi:10.1148/radiol.10092284.

MRI and magnetic resonance may help predict which people at risk for type 2 diabetes will benefit from lifestyle changes, new data suggest.

“Abdominal and liver fat are the two most important factors in predicting whether a lifestyle intervention will be successful,” Jürgen Machann, PhD, of University Hospital Tubingen, Germany, said in a press release.

Machann and researchers performed MRI and magnetic resonance spectroscopy on 243 individuals before and 9 months after a lifestyle intervention. The intervention called for a weight loss of 5%, fat intake reduction to a maximum of 30% of total calories and moderate physical activity at least 3 hours per week.

Each of the participants, which included 144 women and 99 men, was considered at risk for developing type 2 diabetes as a result of obesity (BMI of 27 or greater), impaired glucose tolerance or having a first-degree relative with diabetes.

At baseline, men had about two times the amount of visceral adipose tissue and a smaller amount of adipose tissue (25.9%) compared with women (36.9%). In addition, the baseline insulin sensitivity of men was significantly lower than the sensitivity of women.

The researchers used improved insulin sensitivity to measure the success of the lifestyle intervention. After 9 months, insulin sensitivity improved in 71% of the men and 58% of the women. Individuals with improved insulin sensitivity lost significant amounts of visceral fat (19% for women; 20% for men) and liver fat (35% for women; 44% for men) as well as lost 3% to 5% of body weight.

“The participants who improved their health status as a result of diet and exercise started out with lower baseline levels of abdominal and liver fat,” Machann said.

Individuals who did not improve insulin sensitivity after 9 months of lifestyle intervention lost smaller amounts of visceral fat (4% for women; 6% for men). Men also lost less liver fat (15%), and women gained about 22% of liver fat.

For men, low baseline concentrations of visceral adipose tissue, hepatic lipids and abdominal subcutaneous fat were predictors of successful lifestyle intervention; however, for women, low hepatic lipid levels were the only predictor of success.

“Our results demonstrate that with MRI and magnetic resonance spectroscopy, we can determine who will benefit from dietary changes and exercise and who will need other interventions,” Machann said.