Table 7 Summary of studies evaluating lifestyle intervention effects on markers of insulin sensitivity and glucose homeostasis
Study | n | Population | Training type/intervention length | Groups | Measure | Results |
|---|---|---|---|---|---|---|
Cox et al. [18] | 60 | Average BMI 31.0 kg/m2 20 to 50 yrs Men Nonsmoking Sedentary No substantial weight loss in previous 12 months | 16-week caloric restriction and aerobic exercise intervention | Maintain Diet + Control Exercise Group: 30 min/session at light intensity on 3 days/week Maintain Diet + Vigorous Intensity Group: 30 min/day at 60–70% maximum workload on 3 days/week Energy Restricted Diet + Control Exercise Group: reduced energy intake by 1000–1500 kcal/day + 30 min/session at light intensity on 3 days/week Energy Restricted Diet + Vigorous Intensity Group: reduced energy intake by 1000–1500 kcal/day + 30 min/session at 60–70% maximum workload on 3 days/week | Oral glucose tolerance test | Fasting Glucose Vig. intensity groups had greater decrease compared to light-intensity groups |
Fasting Insulin Significant decrease in Energy Restricted Diet + Vig. Intensity group | ||||||
Glucose AUC Significant decrease in Energy Restricted Diet + Vig. Intensity group Vig. intensity groups had greater decrease compared to light-intensity group | ||||||
Insulin AUC Significant decrease in both Energy Restricted Diet groups Vig. intensity groups had greater decrease compared to light-intensity group Energy restriction groups had greater decrease compared to maintain diet groups | ||||||
Larson-Meyer et al. [82] | 48 | 25 ≤ BMI ≤ 30 kg/m2 Men (25–50 years) and women (25–45 years) Nonsmoking Exercise ≤ twice per week | 6-month caloric restriction and aerobic exercise intervention | Weight Maintenance Control Group Caloric Restriction Group: 25% calorie deficit Caloric Restriction + Exercise: 12.5% calorie intake deficit plus 12.5% increase in exercise energy expenditure Very low-calorie diet: 890 kcal/day intake until 15% weight reduction followed by weight maintenance diet | Intravenous glucose tolerance test | Fasting Glucose No change |
Fasting Insulin Significant decrease in all calorie deficit groups | ||||||
Insulin Sensitivity Index Significant decrease in Calorie Restriction plus Exercise and Very Low-Calorie Diet groups | ||||||
AIRg Significant decrease in all calorie deficit groups | ||||||
Bouchonville et al. [20] | 107 | BMI > 30 kg/m2  > 65 yrs Weight stable previous 12 months Physically inactive with mild-to-moderate physical frailty | 12-month caloric restriction and aerobic exercise intervention | No Exercise or Diet Control Group 10% Diet-Induced Weight Loss Group—prescribed calorie deficit of 500–750 kcal/day Exercise Training without Weight Loss Group—~ 90 min/session (30 min of balance and flexibility, 30 min of aerobic exercise at 70–85% peak HR, 30 min of 1 to 2 sets of 6 to 8 repetitions at 70–85% 1 RM of 9 resistance exercises Diet + Exercise Group—prescribed calorie deficit of 500–750 kcal/day +  ~ 90 min/session (30 min of balance and flexibility, 30 min of aerobic exercise at 70–85% peak HR, 30 min of 1 to 2 sets of 6 to 8 repetitions at 70–85% 1 RM of 9 resistance exercises | Oral glucose tolerance test | Insulin Sensitivity Index Significant increase in Diet group and Diet + Exercise group Significant difference in change between Diet, Exercise, and Control groups vs. Diet + Exercise group |
Insulin AUC Significant decrease in Diet group and Diet + Exercise group Significant difference in change between Diet vs. Control and Exercise vs. Diet + Exercise | ||||||
Glucose AUC Significant decrease in Diet and Diet + Exercise groups Significant difference in change between Diet vs. Control and Exercise vs. Diet + Exercise | ||||||
HOMA-IR Significant decrease in Diet and Diet + Exercise groups Significant difference in change between Exercise vs. Diet + Exercise | ||||||
Gilbertson et al. [19] | 29 | Average BMI: 35.9 kg/m2 18 to 71 yrs Prediabetes Sedentary | 16-week caloric restriction and aerobic exercise intervention | Diabetes Prevention Program + Vigorous Intensity Interval Training: energy restricted diet designed to induce 7% weight loss + 10, 30-s sprints at maximal self-selected intensity (within 10 bpm of maximum HR or RPE 19–20) followed by 4-min active rest at 2.0 mph and 0% grade on 3 days/week Diabetes Prevention Program + Moderate Intensity Continuous Training: energy restricted diet designed to induce 7% weight loss + 60 min/session at 45–55% HR reserve on 3 days/week | Blood draw | Fasting Glucose Significant decrease in both groups over time |
Hemoglobin A1c Significant decrease in both groups over time | ||||||
Fasting Insulin No significant changes | ||||||
HOMA-IR No significant changes | ||||||
Brennan et al. [84] | 84 | BMI ≥ 30 kg/m2 60 to 80 yrs Weight stable previous 6 months Physically inactive Nonsmoking Systolic BP < 150 mmHg and Diastolic BP < 95 mmHg | 6-month caloric restriction and exercise intervention | Health Education Control Group—biweekly general health education seminars on medication on type 2 diabetes management 10% diet-induced weight loss group—prescribed calorie deficit of 500–1000 kcal/day and low-fat diet Diet + Exercise Group—prescribed calorie deficit of 500–1000 kcal/day and low-fat diet + 45 min/session of aerobic exercise at 50–80% HRreserve on 4–5 days/week for 6 months; starting at week 8, added 30 min/session of resistance exercise on 2 days/week (9 exercises focused on major muscle groups; 2–3 sets of 10–12 repetitions each) | Hyperinsulinemic–euglycemic clamp | Fasting Glucose No between-group differences in change |
Fasting Insulin Diet + Exercise group had significantly greater improvement than control group | ||||||
Hemoglobin A1c Diet + Exercise group had significantly greater improvement than control group | ||||||
Rate of Glucose Disposal Corrected for Plasma Insulin Diet + Exercise group improved significantly compared to control After controlling for % weight loss, no significant between-group differences | ||||||
Endogenous Glucose Production Suppression No between-group differences in change |