Local Government Association (LGA) research suggests that one-in-three councils are worried about the density of fast food outlets.

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We found, for example, in research from the Rand Institute that the density of fast food outlets in areas was not necessarily correlated with how fat children were in those areas.

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All of this has been processed such that you can wolf it down fast... chopped up and made ultrapalatable.... Very appealing looking, very high pleasure in the food, very high caloric density.

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Consider celery, often proposed as a negative-calorie food due to its low-calorie count, high water density, and impressive fibre content.

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It predicts a rising global middle class, urban density increases, 50 percent growth in demand for food, water and energy, among many other results.

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Double your vegetable intake and reduce fat -- Both of these changes will significantly decrease the calorie density of your diet without decreasing the volume of food that you consume.

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The researchers twigged that this phenomenon could be used to measure density and, as they report in the Journal of Agricultural and Food Chemistry, they set about this task by erecting a stack of two off-the-shelf neodymium magnets separated by a vertical vial of paramagnetic fluid.

ECONOMIST: Monitor

Theories about why this is happening range from higher levels of obesity, higher density of calories in processed foods, and physical inactivity, to chemicals in food and water.

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