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Combination of exercise and diet has small effects in reducing risk factors for type 2 diabetes

Aguiar EJ, Morgan PJ, Collins CE, Plotnikoff RC, Callister R. Efficacy of interventions that include diet, aerobic and resistance training components for type 2 diabetes prevention: a systematic review with meta-analysis. Int J Behav Nutr Phys Act. 2014;11(2):1-10

Review question

How effective is a combination of diet, aerobic exercise and resistance training in reducing risk factors for type 2 diabetes in pre-diabetic populations?


Type 2 diabetes is a common disease, worldwide. Recommendations for preventing type 2 diabetes include maintaining a healthy weight, eating a healthy diet and exercising. Prevention programs supporting physical activity such as aerobic and/or resistance training have been shown to reduce the number of people diagnosed with type 2 diabetes as well as risk factors for the disease, such as insulin sensitivity and being overweight.  

How the review was done

This is a summary based on a systematic review and meta-analysis of 8 intervention studies with a total of 1,050 participants. The average age of the participants was 55 and 62% were female. The majority of the studies were randomized controlled trials.

The interventions were implemented for approximately 12 months and had an average follow-up of 18 months.  Interventions included supervised individual or group exercise programs with a combination of aerobic and resistance training, as well as a calorie restricted diet and/or a specific dietary plan.

The participants in the intervention group were compared with participants that received counseling, education, or were instructed to maintain usual dietary and exercise patterns.

What the researchers found

Weight Change: A combination of aerobic exercise, resistance training and dietary changes resulted in a modest but statistically significant weight reduction in the intervention group compared to the control group.

Glucose regulation: There was a small but statistically significant reduction in fasting plasma glucose in the intervention group compared to the control group. There was no noticeable impact on other measures of glucose regulation.

Exercise outcomes: A combination of aerobic exercise, resistance training and dietary changes yielded modest, statistically significant improvements in aerobic capacity and muscular fitness.

Dietary outcomes: A combination of aerobic exercise, resistance training and dietary changes resulted in modest, statistically significant reductions in calorie intake in the intervention group compared to the control group.


A combination of aerobic exercise, resistance training and dietary improvements have a modest impact on weight reduction and a small effect in improving glycemic control (fasting glucose level), aerobic fitness and dietary intake in adults who are pre-diabetic or at risk for type 2 diabetes.

Effects of exercise and diet


Effect (SMD)

Weight loss


Fasting plasma glucose




Control group
A group that receives either no treatment or a standard treatment.
Advanced statistical methods contrasting and combining results from different studies.
Randomized controlled trials
Studies where people are assigned to one of the treatments purely by chance.
Risk factors
Aspects making a condition more likely.
Systematic review
A comprehensive evaluation of the available research evidence on a particular topic.

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