Drugs and not diets could be the answer to the fight against middle-aged-spread spread, scientists have suggested.
New research suggests our ability to detect when we are full gets less effecient with age, meaning we eat more before realising we have had enough.
Just a few extra forkfuls of food at every meal can add up to an 1lb of extra weight per year.
However drugs developed to reactivate the system and make obese people feel fuller could be help the rest of us.
Medication could be given to people in their twenties or thirties to regulate appetite.
"It could be used as a preventative and stop the middle-aged spread altogether," said Professor Lora Heisler, chair in human nutrition at the University of Aberdeen, where the study was conducted.
A small set of cells in the brain are responsible for producing hormones called pro-opiomelanocortin (POMC) peptides which regulate appetite and body weight.
However, as people approach middle age those cells stop sending as many signals, and it is harder to feel full.
A new drug, lorcaserin, which is available in the US, can switch the signal back on fully, but it is not yet licensed in Europe.
"Many people wonder why the middle-aged spread happens. You think to yourself, 'I haven't changed anything but I am gaining weight," said Prof Heisler.
"More than half of people in the UK are overweight and one in four is clinically obese. And the fact of the matter is it is very hard to lose weight once it is there, so if we could help people before they get to that stage then that is obviously beneficial."
In the UK more than one third of men and women will be clinically obese by 2030, costing the NHS an extra £19.2bn (€24bn) a year.
Tam Fry of the National Obesity Foundation said the drugs could help overweight people but advised against giving them to young people before they gained weight.
"We're heading in the right direction and drugs like this could be the Holy Grail in fighting the obesity epidemic," he said.
"But the problem with the middle-aged spread is that it is caused by a number of factors. if you exercise and eat healthily then a lot of these problems will go away."