Dietitians were better than doctors at lowering blood cholesterol in the short to medium term, but there was no evidence that they were better than self-help resources. There was no evidence that dietitians provided better outcomes than nurses.The results should be interpreted with caution as the studies were not of good quality and the analysis was based on a limited number of trials.
Lifestyle intervention in overweight individuals with a family history of diabetes.
To assess the effect of lifestyle intervention over 2 years on changes in weight, coronary heart disease (CHD) risk factors, and incidence of diabetes in overweight individuals with a parental history of diabetes.
                Participants (n = 154), who were 30-100% over ideal body weight, had one or both parents with diabetes, and were currently nondiabetic, were randomly assigned to 2-year treatments focused on diet (decreasing calories and fat intake), exercise (goal of 1,500 kcal/week of moderate activity), or the combination of diet plus exercise or to a no-treatment control group. Subjects were reassessed at 6 months, 1 year, and 2 years.
                At 6 months, the groups differed significantly on measures of eating, exercise, and fitness; weight losses in the diet and diet-plus-exercise groups were significantly greater than in the exercise and control conditions. Weight losses were associated with positive changes in CHD risk factors. After 6 months, there was gradual deterioration of behavioral and physiological changes, so that at 2 years, almost no between-group differences were maintained. Differences between groups in risk of developing diabetes were of borderline significance (P = 0.08). Strongest predictors were impaired glucose tolerance at baseline, which was positively related to risk of developing diabetes, and weight loss from baseline to 2 years, which was negatively related; in all treatment groups, a modest weight loss of 4.5 kg reduced the risk of type 2 diabetes by approximately 30% compared with no weight loss.
                Although initially successful, the interventions studied here were not effective in producing long-term changes in behavior, weight, or physiological parameters. However, weight loss from 0 to 2 years reduced the risk of developing type 2 diabetes. Since modest weight loss significantly reduced risk of type 2 diabetes, further research is needed to determine how best to increase the percentage of subjects achieving at least a modest weight loss.