Scientists claim to have established which diets are most likely to work - and keep the weight off in the long term . From high protein to low fat, calorie counters to slimming shakes, we are bombarded by diet plans promising  the holy grail of weight loss. But if you just can't shed the pounds - or keep them off - then help may be at hand. A landmark report claims to have established which diets are most likely to work - and keep the weight off in the long term. The US researchers say very few of these - often very expensive - weight loss plans have solid evidence to back up their claims. In fact, the results suggest only a few programmes have shown their users lose more weight than those not using them. Others produce no better results than people dieting on their own or getting health information elsewhere, while some may actually be harmful to health. Crucially, very few have been shown to keep the weight off permanently. But a handful - including Weight Watchers, the Atkins diet, Jenny Craig and NutriSystem - do appear to be effective, according to long-term studies. The research, from Johns Hopkins University, was prompted by doctors seeing an increasing number of obese or overweight patients wanting to join popular slimming clubs or diet plans. The researchers say reliable proof of which ones work has become increasingly important as doctors and health bosses come under increasing pressure to tackle the obesity epidemic. To draw their conclusions, they first reviewed 4,200 studies involving these diets for solid evidence of effectiveness. However only a few dozen of the studies met the scientific gold standard of reliability - using properly controlled clinical trials. Scroll down for video . Because of this, they ended up examining 11 programs in detail. Three 'high-intensity' programmes were included: Weight Watchers, Jenny Craig and NutriSystem. These incorporate goal setting, self-monitoring, nutritional information and counselling. There were three very-low-calorie meal replacement programmes: HMR, Medifast and OPTIFAST. Five 'self-directed' programmes, Atkins, SlimFast, and the internet-based Biggest Loser Club, eDiets and Lose It!, were also looked at. Of the 11 plans, some were free while those that required replacement meals could cost up to between £380 ($570) and £460 ($682) per month. The high protein, low cab Atkins diet scored well: This was because there was 'gold-standard data' showing that people following the diet lost more weight after one year than those people either dieting on their own or getting health and diet information elsewhere . The researchers say only two programmes are supported by gold-standard data showing that enrolled dieters - on average - lost more weight after one year than those either dieting on their own or getting health and diet information elsewhere. EVIDENCE OF LONG-TERM SUCCESS: Weight Watchers, Jenny Craig . EVIDENCE OF SHORT-TERM SUCCESS: . NutriSystem produced more weight loss at three months than counselling or education alone, but researchers were unable to find any long-term trials . Very-low-calorie meal replacement dieters lost more weight than people not using them in trials lasting 4-6 months. But the only long-term study showed no benefit from such a programme at 12 months. Programmes based on the Atkins diet - high in fat, low in carbohydrates - also helped people lose more weight at six months and 12 months than counseling alone and the approach 'appears promising'. NOT ENOUGH EVIDENCE TO JUDGE: . Slim-Fast and the Internet-based programmes: Biggest Loser Club, eDiets and Lose It! Results were generally 'modest', with participants losing on average between three and five per cent more weight than the studies’ control groups who did not take part. Based on the analysis of the studies, Jenny Craig and Weight Watchers were backed by clinical trials that lasted 12 months or longer and showed those enrolled had a greater weight loss than those not following the plan. NutriSystem also produced more weight loss at three months than counselling or education alone, but researchers were unable to find any long-term trials of that plan. People on very-low-calorie meal replacement plans lost more weight than many other dieters in the first four to six months. But there was only one long-term study, which showed no benefit from such a programme at 12 months. But these diets also carry higher risks of complications, such as gallstones, the researchers found. Programmes based on the Atkins diet - high in fat, low in carbohydrates - also helped people lose more weight at six months and 12 months than counseling alone and the approach 'appears promising'. But no definite conclusions could be made about Slim-Fast and the internet-based programmes, they say. Jeanne Clark, professor of medicine, said: 'We want people to experience the health benefits of weight loss - lower blood pressure, cholesterol and blood sugar, and lower risk of developing diseases like diabetes . People on very-low-calorie meal replacement plans lost more weight than many other dieters in the first four to six months. But there was only one long-term study, which showed no benefit from such a programme at 12 months. 'Those benefits are long-term goals - so losing weight for three months, then regaining it, has limited health benefits. 'That’s why it’s important to have studies that look at weight loss at 12 months and beyond.' Dr Kimberly Gudzune assistant professor of medicine, added: 'Clinicians could consider referring patients who are overweight or obese to Weight Watchers or Jenny Craig. 'Other popular programmes, such as NutriSystem, show promising weight-loss results, but additional studies evaluating long-term outcomes are needed.' The findings, published in the Annals of Internal Medicine, come with a call for more rigorous tests of the programs for longer periods of time, so effectiveness can be better judged. The authors added: 'Doctors need to know which programmes have rigorous trials showing they work, but they haven’t had much evidence to rely on. 'Our review should give clinicians a better idea of what programmes they might consider for their patients.' The researchers looked at the evidence for 11 different weight loss plans . Weight Watchers: A calorie controlled diet, which assigns every food a points value, based on its protein, carbohydrate, fat and fibre. Choices that fill a person up the longest 'cost' the least, and nutritious foods cost less than those with 'empty' calories, such as junk food. Atkins: Involves limiting carbohydrates and increasing the proportion of protein and fat in the diet. Designed to 'flip the body's metabolic switch' from burning carbs to burning fat. Claims to limit blood sugar and insulin spikes, which cause hunger and cravings, and result in overeating and weight gain. Jenny Craig: A diet in which people are able to choose from a range of pre-packaged, microwaveable meals, which they can supplement with vegetables, wholegrains and low-fat dairy. Dieters discuss meal plans with a counsellor and also have access to an advice helpline. NutriSystem: A prepaid meal plan with 28 days of meals delivered to the dieter’s door, which can be supplemented with fresh fruit and vegetables. Menus provide a mix of low-glycaemic carbohydrates, fibre, and lean protein. HMR: A meal replacement system, including shakes and microwave meals, supplemented with fresh fruit and vegetables. Biggest Loser Club: Online weight loss plan linked to the brutal TV show of the same name. Dieters get meal plans, online workout videos and online support. SlimFast: Involves substituting two daily meals with an energy-restricted replacement. Products include powders, shakes, meal bars and snacks. eDiets: Online weight loss tool with 'a variety of digital diet plans, nutritional products and supplements to help members'. Medifast: Consists of pre-planned meals which create a calorie-deficit to aid weight loss. Products include shakes, smoothies, bars, crisps, cereals and soups. Lose it! Helps users set a daily calorie budget, track their food intake and exercise, and 'stay motivated to make smarter choices'. Optifast: Meal replacement plan including shakes, soups, bars, protein drinks and vitamin, mineral and fibre supplements.
Researchers examined 4,200 studies and selected 11 weight loss plans.
Included Atkins, Jenny Craig, meal replacements and online support sites.
Wanted to see how successful they were at first and in the long term.
Very few plans had evidence they worked better than getting information elsewhere for free - or that they helped weight stay off permanently.