The neurological argument is very much in its infancy, with very little in the way of true experimental evidence, yet laypeople throw it around as if it's well-established theory. Neuroscientists, however, are pretty humble and hedging about it: every paper on the subject is littered with mights, maybes, perhapses, and "more investigation is needed"s.
The scientists at The University of Nottingham and Tehran University of Medical Sciences set out to test the effect of replacing diet drinks with water by comparing weight loss in two randomly selected groups of type 2 diabetic women during a 24 week diet programme. The results are published in the journal Diabetes, Obesity and Metabolism.
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Dr Hamid Farshchi, from The University of Nottingham’s School of Life Sciences, said: “Our results are very interesting. They show that the women drinking water after their main meal at lunch time over 24 weeks lost on average 1.16kg more than the women who drank diet drinks after their meal. We think that by drinking water instead of sweet-tasting diet drinks, the women may be adhering better to the weight loss diet because artificial sweeteners may increase desire for sweetened and more energy dense foods.