Losing inches has been proven to be even harder than first thought
As if we didn't have enough trouble trying to shift the pounds, scientists are now claiming that losing weight is twice as difficult as official guidelines claim.
Researchers found that people lost only half as much weight as expected in a year if they followed advice given by the NHS and US health organisations.
Cutting down calories slows your metabolism down, which means that weight loss will start to dwindle and eventually stop.
To help redress the balance, scientists from the US National Institute of Diabetes and Digestive and Kidney Disease have programmed an online calculator which designs a personalised weight loss plan based on information about your diet, physical activity and body shape.
The calculator allows would-be slimmers to adjust their expectations and gain a more realistic picture of what they can expect to achieve.
"We know that if you cut the calories in somebody's diet their metabolism starts to slow down, and it slows down more and more the more weight that is lost. So eventually reach a plateau," explains Dr Hall, at the annual meeting of the American Association for the Advancement of Science.
He says that due to the way in which the metabolism slows weight loss, dieting away 100 calories daily would lead to the weight loss of just 10lbs in three years. Five of which would be in the first year.
The slimming aid - available at bwsimulator.niddk.nih.gov - is designed to assist researchers rather than members of the public, although anyone can access it.
"Instead of using that old rule of thumb that we now know is incorrect, people can plug in what their goal weight might be in a specific period," says Dr Hall of the online calculator.
"What the model will do is simulate what changes in diet and exercise that person will have to do to achieve that goal weight and even more importantly what they have to do permanently to maintain that weight loss."