Background:
Though a high amount of visceral fat is associated with insulin resistance, which can lead to type 2 diabetes (T2D) and cardiovascular diseases (CVDs), less is known about whether lifestyle modification (weight loss diet and exercise) induced changes in visceral fat are associated with improvements in glycemia.
Methods:
We randomized 77 individuals aged 35-65 years with T2D or pre-diabetes to 6-months of weight loss diet (D); or D combined with supervised moderate-intensity exercise training (D+E). Study measures were total abdominal, visceral and subcutaneous fat volumes by magnetic resonance imaging, aerobic fitness expressed as VO
2
peak during treadmill testing, body mass index (BMI), and HbA1c levels from blood samples.
Results:
Of 77 subjects (mean age, 54.8±7.8 years; mean BMI, 34.5 ± 4.7 kg/m
2
, women, 77.9%; Whites-65%, Blacks-34%, Asians-1%), n=37 had T2D and n=40 had pre-diabetes. At 6 months, both D and D+E groups improved from baseline (p<0.05 for all) but did not differ in their changes for body weight (D: -6.04 ± 4.54 kg; D+E: -6.68 ± 4.48 kg, p= 0.61 for the group differences in change), abdominal total fat (D: -101.93 ± 68.67 cm
2
; D+E:-104.16 ± 72.37 cm
2
, p= 0.92), visceral fat (D:-25.53 ± 39.44 cm
2
; D+E:,-23.24 ± 35.62 cm
2
, p=0.85), HbA1c (D:0.04 ± 0.46%; D+E:0.03 ± 0.63%, p=0.96), and VO
2
peak (D: 2.26 ± 3.92 ml/kg/min ; D+E:3.71 ± 2.65 ml/kg/min, p=0.11). In a multivariate analysis, adjusting for baseline visceral fat, T2D status, body weight loss and increases in aerobic fitness, a reduction in HbA1c (β=-0.49, p =0.007) was associated with a reduction in visceral fat (R
2
=0.34, p=0.02).
Conclusion:
The key finding was that diet or diet plus exercise-mediated reductions in visceral fat was associated with reduced HbA1c among individuals with T2D or pre-diabetes. These data contribute to growing body of evidence of the benefits of reducing abdominal obesity, in this case, resulting in better glycemic control in T2D and pre-diabetes.
Effect of a High-Protein, High-Monounsaturated Fat Weight Loss Diet on Glycemic Control and Lipid Levels in Type 2 Diabetes
