to review the current knowledge about nonpharmacologic approaches in the prevention and early treatment of type 2 diabetes . this study reviewed the research reports dealing with nonpharmacologic interventions aimed at preventing type 2 diabetes with early lifestyle interventions . the results from the randomized controlled trials all show that people with impaired glucose tolerance who received enhanced lifestyle advice had significantly lower ( on average 50% reduced ) incidence of type 2 diabetes compared with those allocated to receive  usual care . individuals who were able to correct their lifestyle habits as recommended for usual healthy life patterns were mostly protected against type 2 diabetes . thus , compelling evidence exists that most of the cases of type 2 diabetes can be prevented or at least the onset of the disease can be significantly delayed . randomized controlled trials have unequivocally demonstrated that lifestyle management is highly efficient in the prevention and also in the early management of type 2 diabetes . this evidence of lifestyle modification in diabetes prevention is stronger than for most other multifactorial diseases . in the early randomized intervention study in malmhus , sweden ( 19 ) , lower rates of type 2 diabetes was found in igt men randomized to dietary intervention compared with those who received no therapy . more recently , several trials have tested the efficacy of lifestyle intervention in prevention of type 2 diabetes . the feasibility of diet and exercise intervention in men with igt was assessed in another study in malm , sweden ( 20 ) . because the reference group comprised of men who did not want to join the intervention , the groups were not randomly assigned . the lifestyle intervention aimed at reducing the intake of refined sugar , simple carbohydrates , fat , saturated fat , energy , and alcohol and an increase in the intake of complex carbohydrates and vegetables . physical activity training consisted of two weekly 60-min sessions with various dynamic activities . by the end of the 5-year study period , 11 and 29% of the men in the intervention group and reference group had developed type 2 diabetes , respectively . overall , the progression to diabetes in these swedish men was relatively low , even in the reference group compared with the data from the observational studies ( 1 ) . the intervention resulted in significant changes in lifestyle and physiological parameters . in another study , 577 subjects with igt were assigned either to a control , exercise alone , diet alone , or exercise plus diet group in da - qing , china ( 14 ) , using a cluster - randomized trial design . participants were assigned to clinics for dietary intervention and were encouraged to reduce weight if bmi was 25 kg / m ( 61% of all participants ) aiming at 23 kg / m ; otherwise high - carbohydrate ( 5565% of energy ) and moderate - fat ( 2530% of energy ) diet was recommended . the participants were encouraged to increase their level of leisure - time physical activity by at least 12  units  per day in clinics assigned to exercise intervention . one unit would correspond for instance to 30 min slow walking , 10 min slow running , or 5 min swimming . the cumulative 6-year incidence of type 2 diabetes was lower in each of the three intervention groups ( 4146% ) compared with 68% in the control group . the results of the finnish diabetes prevention study ( dps ) provided the first convincing evidence from a proper randomized controlled trial that type 2 diabetes can be prevented by lifestyle modification ( 21 ) . a total of 522 individuals with igt were randomized to either an intensive lifestyle or a control intervention : during an average of 3.2 years of follow - up , type 2 diabetes incidence was reduced by 58% in the lifestyle group . the lifestyle intervention goals were 1 ) reduction in weight of 5% , 2 ) total fat intake < 30% of energy , 3 ) saturated fat intake < 10% of energy , 4 ) fiber intake 15 g/1,000 kcal , and 5 ) moderate exercise for 30 min / day . during the first year of the study , body weight decreased on average 4.5 kg in the intervention group and 1.0 kg in the control group subjects ( p < 0.0001 ) . indicators of central adiposity and fasting glucose and insulin , 2-h postchallenge glucose and insulin , and a1c were all reduced significantly in the intervention group compared with the control group at 1-year examination ( fig . changes in clinical and metabolic characteristics among the intervention and control group participants of the dps . 2h - p - gluc , 2-h plasma glucose ; diast , diastolic blood pressure ; f - p - gluc , fasting plasma glucose ; s , serum ; syst , systolic blood pressure . diabetes prevention program ( dpp ) ( 22 ) recruited 3,234 individuals with igt ( and fasting plasma glucose 95 mg / dl ) who were randomized to receive intensive dietary and exercise counseling , metformin , or placebo . the main aims of the intervention were 7% weight reduction and 150 min / week moderate physical activity . the relative risk reduction after 2.8 years was 58% in the lifestyle intervention group compared with the placebo group . the effect of lifestyle was higher than the effect of metformin , which showed 35% relative risk reduction . during the first year of the intervention , weight reduction was 5.6 kg ( 6% ) , with slight , gradual regain to the end of the study at year 4 ( 23 ) . the indian diabetes prevention program ( 14 ) recruited 531 people with igt who were randomized into four groups ( control , lifestyle modification , metformin , and combined lifestyle modification and metformin ) . lifestyle modification included advice on physical activity ( 30 min of brisk walking per day ) and reduction in total calories , refined carbohydrates and fats , avoidance of sugar , and increase in fiber - rich foods . after median follow - up of 30 months , the relative risk reduction in type 2 diabetes incidence was with lifestyle modification , 26.4% with metformin , and 28.2% with lifestyle modification and metformin , as compared with the control group . thus , there was no added benefit from combining the pharmacologic and lifestyle interventions . the japanese trial ( 24 ) included 458 igt men randomized to receive either intensive lifestyle intervention ( n = 102 ) or standard intervention ( n = 356 ) . the aims of the intensive intervention were body weight reduction if bmi was 22 kg / m ( otherwise , to maintain present weight ) , to consume large amounts of vegetables while reducing the amount of other foods by 10% , reduction of fat ( < 50 g / day ) and alcohol intake ( < 50 g / day ) , and physical activity > 3040 min / day . the cumulative 4-year incidence of type 2 diabetes in the intervention group was 67% lower than in the control group . body weight decreased by 2.2 and 0.4 kg in the intervention and control groups , respectively . the trials listed above have demonstrated the benefits of healthy lifestyle on delaying the deterioration of glucose tolerance to manifest type 2 diabetes , at least as long as the intervention continued . data on possible long - term effects of such active lifestyle counseling are scarce . the 12-year follow - up of the malm study ( 25 ) revealed that mortality among men in the former igt intervention group was lower than in the control group ( 6.5 vs. 14.0/1,000 person - years , p = 0.009 ) . in a median 7-year follow - up of the dps , the marked reduction in type 2 diabetes incidence was sustained ( 13 ) . more importantly , after a median postintervention follow - up of 3 years , type 2 diabetes incidence was 4.6 and 7.2 per 100 person - years in the intervention and control groups , respectively ( log - rank test , p = 0.0401 ) , i.e. , a 36% additional risk reduction . the absolute risk difference between groups increased during the postintervention period : intensive lifestyle intervention for a limited time can yield long - term benefits on type 2 diabetes risk in individuals with igt . the 20-year follow - up of the original da qing cohort showed that a lower type 2 diabetes incidence persisted in the lifestyle intervention groups ( combined ) compared with control participants . the risk reduction remained essentially the same also during the postintervention period ( 26 ) . ( 26 ) observed no statistically significant differences in cvd events , cvd , or total mortality between the control group and the combined intervention groups , but cvd mortality tended to be lower ( 17% ) among individuals who had received lifestyle intervention . in most of the published prevention trials , the main aim was to see if comprehensive lifestyle intervention reduces type 2 diabetes risk . in the chinese prevention study ( 14 ) , an attempt to determine whether diet or exercise intervention is more effective by randomizing the participating clinics to diet only , physical activity only , or diet plus physical activity intervention revealed no difference in outcome between the two interventions . in the dps , the risk of being diagnosed with diabetes was strongly associated with the number of lifestyle goals achieved ( 21 ) . success in achieving the intervention goals in the dps was estimated from the food records and exercise questionnaires . the success score ( from 0 to 5 ) there was a strong inverse correlation between the success score and the incidence of diabetes during the total follow - up . this was especially apparent when the success in achieving the goals was assessed at year 3 , which probably reflects the importance of sustained lifestyle changes ( 13 ) . the hazard ratios were 1.00 , 0.87 , 0.67 , 0.70 , and 0.23 , for success scores from 0 to 45 , respectively ( p for trend < 0.001 ) . the effects of various components of intervention are interesting , and therefore some post hoc analyses related to this issue were completed . the independent effects of achieving the success score components at 3-year examination were assessed by including each of the five lifestyle goal variables individually in a cox model ( table 1 ) . univariate hazard ratios for diabetes incidence ( 95% ci ) were 0.45 ( 0.310.64 ) for weight reduction from baseline , 0.65 ( 0.450.95 ) for intake of fat , 0.59 ( 0.311.13 ) for intake of saturated fat , 0.69 ( 0.490.96 ) for intake of fiber , and 0.62 ( 0.460.84 ) for physical activity , comparing those who did or did not achieve the respective goal . when all the five success score components were simultaneously included in the cox model , the multivariate - adjusted hazard ratios for diabetes ( 95% ci ) were 0.43 ( 0.300.61 ) for weight reduction , 0.80 ( 0.481.34 ) for intake of fat , 0.55 ( 0.261.16 ) for intake of saturated fat , 0.97 ( 0.631.51 ) for intake of fiber , and 0.80 ( 0.571.12 ) for physical activity . furthermore , weight change was significantly associated with the achievement of each of the other four lifestyle goals , and consequently , success score was strongly and inversely correlated with weight reduction ( 27 ) . multivariate logistic regression model to predict diabetes during a 10-year follow - up correspondingly , the reduction in body weight was reported to be the main determinant of risk reduction in the u.s . after adjustment for other components of the intervention , there was a 16% reduction in diabetes risk per 1 kg weight lost during the first year of the intervention . furthermore , lower percent of calories from fat and increased physical activity predicted weight loss , and increased physical activity was important to help sustain weight loss . achieving the physical activity goal of 150 min / week reduced diabetes risk , especially among those participants who did not achieve the weight reduction goal of 7% , with risk reduction of 44% compared with those who achieved neither the weight reduction nor the physical activity goal . these findings suggest that dietary composition and physical activity are important in diabetes prevention , but their effect on diabetes risk is primarily mediated through resulting weight reduction . nevertheless , because of multicolinearity it should also be noted that in the indian diabetes prevention program ( 15 ) and chinese prevention study ( 14 ) , the participants were relatively lean , and there was no large change in body weight , but despite that , a remarkable reduction in diabetes risk was apparent . thus , in these studies , components of the intervention other than weight control were responsible for the beneficial effects on diabetes risk . with compelling evidence that type 2 diabetes can be prevented or delayed , strategies to implement the primary prevention of type 2 diabetes both in high - risk subjects as well as at the population level are urgently needed . while type 2 diabetes prevention trials rigorously defined populations by explicitly characterizing their glycemic status , these studies did not include all groups at risk for developing type 2 diabetes . methods that can also define other groups at high risk for developing type 2 diabetes have been recently developed and are increasingly used in several countries ( 28 ) . the recent analysis of the dps has also shown that such people will significantly benefit from lifestyle interventions ( 27 ) . a prospective study based on the data from the u.k . estimated the association between the achievement of the five lifestyle goals used in the dps and the type 2 diabetes risk developing diabetes during a 4.6-year follow - up ( 29 ) . the incidence of type 2 diabetes was inversely related to the number of goals achieved ( p < 0.001 ) . none of the participants who met all five of the goals ( 0.8% of the total population ) developed diabetes , whereas the risk of diabetes was highest in those who did not meet any of these goals . if the entire population were able to meet one more goal , the total incidence of diabetes is predicted to decrease by 20% . this finding suggests that health promotion interventions that result in an increase in healthy lifestyle in the general population might significantly reduce the growing burden of type 2 diabetes . groups that will be the targets for prevention efforts can be identified through several reasonably effective strategies . however , there is no universal well - tested method that will identify all at high risk for developing type 2 diabetes , and there may be some variation in the optimal strategies for different populations and regions around the world . it is also important to realize that the identification of people having a high risk of type 2 diabetes or asymptomatic type 2 diabetes is not identical with the diagnosis of type 2 diabetes . in practice , we can identify people at high risk with simple and cost - efficient tools . the main question , however , is how to implement an efficient preventive strategy in individuals identified to be at high risk , i.e. , how to translate the results of the recent successful type 2 diabetes prevention trials to a real - life setting ( 30 ) . much attention has been put on the biochemical methods for the assessment of glycemia in the early diagnosis of type 2 diabetes , but much less on the coverage of the detection of asymptomatic type 2 diabetes . the evidence is compelling that without applying an oral glucose tolerance test or an assessment of postprandial glucose , a large proportion of early cases of type 2 diabetes will remain unrecognized ( 31 ) . the international diabetes federation consensus group recently prepared a document on the prevention of type 2 diabetes ( 32 ) . this shows that the international diabetes community is now ready to accept the principle that the primary prevention of type 2 diabetes must be considered as an essential part of public health policy for diabetes . the american diabetes association consensus development conference in 2006 outlined principles regarding impaired fasting glucose ( ifg ) and igt and interventions to be applied among such individuals ( 26 ) . the american diabetes association consensus group also recommended lifestyle intervention initially for people with ifg or igt ( weight control and physical activity ) but does not mention diet at all . if both ifg and igt are present as well as additional risk factors ( and most of such people have additional risk factors ) , then a combination of lifestyle intervention and metformin is recommended . however , the evidence is not there to show that the combination of lifestyle and metformin is effective ; on the contrary , the results from the indian diabetes prevention program suggest that there is no additional benefit from metformin over and above lifestyle intervention ( 15 ) . it is not clear how much antidiabetic drugs can help in preventing progression from ifg or igt to overt diabetes and what is their overall costs and risk / benefit ratio in the long term . it is evident that long - term effects of lifestyle interventions are highly beneficial and that long - term costs are very low ( 13,26 ) . ( 33 ) in their analysis stress that the real answer to reductions in incidence and prevalence of diabetes is in social policy , not in medical care .