Diet soft drinks don't help with weight loss and could be making you ...

A DIET soft drink a day could be making you fat, more likely to get diabetes and at higher risk of cardiovascular disease.

Artificial sweeteners used in these drinks are meant to give you the taste without the calories but a major review of scientific studies suggests they may instead interfere with the body's normal energy regulation.

Researcher Susan Swithers of Purdue University in the US says sweet tastes normally trigger a psychological response that signals the arrival of nutrients in the stomach.

However, research shows when artificial sweeteners are consumed no such energy burst follows the taste and over time this appears to weaken the body's natural response to a sweetness.

'By weakening the validity of sweet taste as a signal for caloric post-ingestive outcomes, consumption of artificial sweeteners could impair energy and body weight regulation,' she says in a paper published in Trends in Endocrinology and Metabolism.

The research looks at 15 large health studies from around the world that included data on artificial sweetener consumption over the past 40 years.

The clear conclusion was that there was 'little support for artificially sweetened beverages in promoting weight loss or preventing negative health outcomes such as Type 2 Diabetes, metabolic syndrome (increased blood pressure, high fasting blood glucose, large waist circumference, high cholesterol), and cardiovascular events,' the study says.

Instead, a number of the studies suggested that people who regularly consumed artificially sweetened beverages were at increased risk compared with those that did not.

The San-Antonio Heart Study of 1250 men and women found risk of weight gain and obesity were greater in those consuming artificially sweetened beverages than those who did not.

A European study of over 66,000 women and a health professionals study of around 40,000 men found the risk of Type 2 diabetes doubled for the heaviest drinkers of artificially sweetened beverages.

The Nurses Health Study which included over 88,000 women found the risk for type 2 diabetes was increased by consuming only one artificially sweetened beverage a day.

While a study of normal weight children assigned to drink a single artificially sweetened beverage a day gained less weight than those who consumed one sugar sweetened beverage a day.

A second study of overweight and obese adults who substituted water or artificially sweetened beverages for sugar sweetened beverages found while there was an improvement in blood sugar levels in those consuming water, no such effect happened in those consuming artificially sweetened beverages.

The study comes as new research shows increasing exercise rates in the US have not helped cull rising obesity rates.

Obesity rates increased across the US from 2001 to 2009 despite an increase in the prevalence of sufficient physical activity and the George Institute's Bruce Neal says the most likely explanation is the 'excess of energy provided by the food supply'.

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