Increasing amounts of research indicate that dieting is more often a contributor to long-term eating and weight issues than it is a passport to lasting and relaxed weight control.

Whilst repeated dieting does not automatically lead on to the very serious eating disorders of anorexia and bulimia, constant unhappiness with eating and self-image can certainly be harmful to self-esteem and, indeed, physical and mental health.

Yale University's Prof. Kelly Brownell coined the notion of Yo-Yo Dieting 20 years ago. The research was a major breakthrough into realizing the limitations of interfering too much with a natural relationship with food and eating.

Yo-Yo Dieting is the widely understood notion of periods of crash weight reduction being followed by periods of weight regain once the artificial eating regime is relaxed. Subsequent studies have indicated that major health risks, particularly of heart disease, are associated with these dieting cycles.

Now, new research by a weight-control charity suggests that many more people than previously recognized are living their lives dominated by anxieties over eating and dieting.

The Weight Foundation says that obsessive dieting is to blame for great misery and that too little help is on offer for individuals who spend their lives locked into depressing and often unhealthy dieting regimes.

For many women, the panicky run-up to peak holiday time - and also the Thanksgiving period - are triggers for fresh cycles of self-starvation, with the lost weight often creeping back on.

However, The Weight Foundation is discovering that the extent of the worldwide dieting misery is much wider than these weight-loss and regain rituals.

The research being conducted by the charity's founder through the UK's Manchester Metropolitan University is shedding light on the millions of dieters worldwide who suffer long-term distress but do not undergo any dramatic swings in weight.

"The accepted pattern of dieting is what has been called Yo-Yo-ing," explains Evans, a 46 year old Cambridge University social sciences graduate, professional motivational trainer and private therapist.

"Instead, we call this Swinger dieting because we find whether and how quickly weight returns depends on many factors and is not automatic like a Yo-Yo. However, the more you look at what is actually going on in the privacy of people's own homes, this is just the tip of the dieting iceberg."

Flatliner dieting is identified as being a constant battle between "good" and "bad" foods, with people varying between treating and punishing themselves with food. These mini-dieting cycles can be packed within as short a time as a single day. The term Flatliner refers both to the lack of any jagged peaks of weight gain and loss and also to the emotional flatness and misery usually experienced with this lifestyle. There is constant tension between overeating and self-denial.

Lifer dieting refers to people who never really come off a diet at all, even though they may swap diets now and then. Lifers fear that breaking their strict eating regime for just a single day might spell disaster. Occasions such as weddings and family gatherings are times of high anxiety.

Evans says, "The majority of research to date on eating and dieting problems has tended to concentrate on the extreme areas of Anorexia and Bulimia. What we are finding, particularly horrible as these conditions are, is that there are potentially huge numbers of dieters experiencing great distress."

As with all unrecognized conditions, many of these people suffer in silence, without understanding or support. The Weight Foundation is referring to all types of dieting which tend to dominate an individuals' lifestyles as Hardcore Dieting.

The charity is seeking to understand what pressures and motivations hold obsessive dieting behavior in place and is finding in both the U.S and the UK that there is a widespread cultural acceptance that a dieting lifestyle is the morally correct lifestyle.

It is Evans' goal to develop an international network of committed individuals who can mentor dieters to move away from depressing and destructive habits. The philosophy is that by treating food and eating as mainly just a necessity of life, weight will find its natural ? normally lighter ? level.

"The key difference between happily slim people and unhappily overweight individuals is that, for the former, food plays a very small part in their lives."

"Dieting can often make people overweight and it will always make them unhappy. The key to lasting weight control is to enjoy a healthy and natural relationship with food. It is only by developing a thorough understanding of Hardcore Dieting that this message will stop falling on deaf ears," says Evans.

The Weight Foundation's website features The Hardcore Dieting Index, a self-diagnostic questionnaire for dieters.