These are the gold standard randomized control trials or intervention studies, in which a control group consuming soda is monitored for weight gain over time against a group which stops drinking soda (and all other dietary and lifestyle factors are controlled for).

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"The evidence that has come up is of great interest but it's all either anecdotal or epidemiological and not the intervention studies that are going on right now that will lead to answers in the next three years, " said Robert Wood, director of Pediatric Allergy and Immunology at Johns Hopkins University School of Medicine.

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For example, one of the most widely cited intervention studies on soda and weight, ( Ebbeling et al. 2006) took 103 adolescents aged 13 to 18 who regularly consumed soda and randomly assigned them to either a group that received no calorie beverages for six months by way of home delivery or a control group that carried on drinking soda as normal.

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In Walton's studies, the intervention increased subjects' happiness, improved their health and reduced cognitive activation of negative stereotypes for several years after the initial intervention.

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Studies show that early intervention can significantly improve a child's IQ, language ability and social skills.

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Yet, although a number of studies have suggested that intervention by institutions over matters of corporate governance can boost profits and share prices in the long run, the results are inconclusive, especially when considering the risk of angering customers.

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The speed of the court's decision likely reflects unwelcome political intervention in the judicial system, said Dr. Omar Ashour, director of Middle East Studies at the University of Exeter and a visiting scholar at the Brookings Institution in Doha.

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