Obesity reviews : an official journal of the International Association for the Study of Obesity
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This paper brings together some modern statistical methods to address the problem of missing data in obesity trials with repeated measurements. Such missing data occur when subjects miss one or more follow-up visits, or drop out early from an obesity trial. A common approach to dealing with missing data because of dropout is 'last observation carried forward' (LOCF). ⋯ We review the need for obesity trials, the assumptions that must be made regarding missing data in such trials, and some modern statistical methods for analysing data containing missing repeated measurements. These modern methods have fewer limitations and less restrictive assumptions than required for LOCF. Moreover, their recent introduction into current releases of statistical software and textbooks makes them more readily available to the applied data analyses.
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Dietary fat intake has been blamed for the increase in adiposity and has led to a worldwide effort to decrease the amount of fat in the diet. However, the comparative efficacy of this approach is debatable. Whilst short-term dietary intervention studies show that low-fat diets lead to weight loss in both healthy and overweight individuals, it is less clear if a reduction in fat intake is more efficacious than other dietary restrictions in the long term. ⋯ There were no significant differences between low-fat diets and other weight-reducing diets in terms of sustained weight loss. Furthermore, the overall weight loss at the 12-18-month follow-up in all studies was very small (2-4 kg). In overweight or obese individuals who are dieting for the purpose of weight reduction, low-fat diets are as efficacious as other weight-reducing diets for achieving sustained weight loss, but not more so.