According to a new study published in peer-reviewed journal Neurology, being obese or overweight in middle age increases the risk of developing dementia. Being overweight, we are told, raises your risk of developing heart disease, cancer, diabetes and even eye problems. Obesity has also been connected to an increased risk in childbirth. And although this latest research sounds like a brand-new conclusion on an important concern for the overweight, it has in fact been studied before – with conclusions on the link between weight and dementia being reported in both 2005 and 2006.

A great deal of money must have been spent to support these research projects. Significant funding to tell us what we already know: that obesity is a health risk. It is undesirable. It is very bad. As someone who is both middle aged and obese, I am very well aware of the risks associated with my current size (just shy of morbidly obese with a fluctuating BMI of between 38 and 39). I don't need more research to tell me how dangerous it is. I need to know how to cure it.

Diets don't work. They may have a short-term effect but, unless you can maintain a celebrity-like iron grip on your eating for the rest of your life (and few can) they are not a permanent solution and can have negative effects. For some people, like me, they don't work at all, because of complex endocrine deficiencies that are only recently being properly investigated, documented and understood. People tend not to believe that a medical condition can cause weight gain, but the little-known – and devastating – Cushing's disease is one such cause, alongside more well-recognised but not yet fully understood illnesses including hypothyroidism and PCOS (sometimes referred to as metabolic syndrome because, yes, it does affect men too).

It's easily understood that we are less active and eat more processed food than our ancestors did, and we have seen our size increase as a result – not just weight but height and shoe sizes, too. But that's not the whole story. Why do some people manage to eat as much as they like and yet remain slim, while others gain weight even on a restricted diet, with healthy levels of exercise? Why are children increasingly affected by obesity? There are pieces of the puzzle – the social elements, the dietary issues, the medical problems, the genetic picture, the psychological factors – that are still missing. And it is on that absent information that our research efforts ought to be focused.

Whatever the origin of an individual's obesity might be, living with extra weight is a nightmare. I am regularly insulted by strangers in the street. Worse, my 12-year-old daughter, also affected by the genetic condition that has caused my weight gain, experiences the same thing. Some weeks ago she was verbally abused in public by a young couple who told her that she was "disgusting" and "gross" and should stop eating; these words, along with the epithet "fat bitch", are all too familiar to me.

We don't need to be told that our obesity can lead to myriad further health problems; we need to know about the causes, not the consequences. With that aim in mind, I gave permission for my daughter's blood to be sent to the research team at Addenbrooke's hospital in Cambridge, where the genetic causes of obesity are being examined. They are working with doctors around the country who look after children who are overweight. In the last 12 years, they have discovered eight different genes that, when affected, can cause obesity. The discovery of one gene led to actual treatment options for affected patients and the researchers are using increasingly cutting-edge technology to investigate genetic influences on weight gain.

When I enquired about the scope of the study, Dr Sadaf Farooqi, Wellcome Trust senior clinical fellow and reader in human metabolism, explained:

"We know that when you look at weight problems across populations, they usually stem from a combination of environmental factors that act upon genes. But not everyone in that same environment gains weight in the same way. We seek to understand why particular people are especially prone to gaining weight and to identify major genetic influences on heaviness, especially where a person has gained weight from a young age."

This is the kind of research that I would hope to see reported far more widely in the future. This is where the funding should go. "Our research is very important to those suffering from obesity," Farooqi told me. "The greatest distress for patients is that nobody is sympathetic, including many healthcare professionals. There is a lot to do in terms of challenging perceptions."

There is. And studies that help us to do exactly that are of far greater value than the research that tells us what might happen to us if these answers are not found.