A major new scientific study of diets shows that intermittent fasting sheds most weight but the Mediterranean diet is healthier as well as easier to stick with long-term.

Overall they found the Med diet is the most effective way to lose weight because more people were on it a year after starting than other fad diets like the paleo or 5:2.

A study found almost six in ten (57 per cent) were still on the Med diet at the end of the year.

This compared to 54 percent of those who chose the 5:2 diet and just a third (35%) who opted for the paleo 'caveman' eating plan.

​Those on the Med diet also saw big improvements in their blood pressure and glucose levels - reducing the risk of cardiovascular disease and diabetes.

It encourages consumption of fruit, vegetables, whole-grain breads and cereals, legumes, nuts, seeds and olive oil with moderate amounts of fish, chicken, eggs and dairy and red meat once a week or less.

The paleo diet consisted of less-processed foods with an emphasis on eating fruit and vegetables, animal proteins, nuts, coconut products and extra-virgin olive oil.

While "original" Paleo diets strictly exclude all legumes, dairy and grains, this study used a modified version including some dairy as well as up to one serving daily of legumes and grain-based food.

Co-lead author Dr Michelle Jospe aid the results showed people found the Mediterranean diet to be the easiest to adhere to.

She said: "Our participants could follow the diet's guidelines more closely than the fasting and paleo diets and were more likely to stay with it after the year, as our retention rates showed."

But the study found those who managed to stay on the fasting diet where participants ate a quarter of their normal calories on two days of the week lost slightly more weight - an average of nine pounds over the 12 months.

This compared to six and four pounds for the Med and paleo diets respectively, reports the American Journal of Clinical Nutrition.

The researchers at the University of Otago in Canada said the findings supported the idea there wasn't a single "right" approach to diet.

Co-lead author Dr Melyssa Roy said: "In the real world, the one right way to lose weight and eat right is that you can find what suits you the best, and whatever diet is the best is the one you stick to.

"If you choose something that suits you, and is basically a selection of healthy foods, and perhaps eating a bit less often, you can actually get real-world benefits and just live a normal life, and lose weight and see improvements in your health."

The study also showed expensive weight-loss products or ongoing dietitian advice were not necessary to help.

Dr Roy said: "You can actually just choose a particular way of eating and apply it to your own life."

The average weight loss didn't sound like a lot but it was enough to have health benefits.

Dr Roy said: "These people just literally got given advice on how to follow a diet then got left alone and then at least half of them actually managed to lose an amount of weight that from a medical point of view is clinically significant.

Most of the 250 participants (54%) chose the fasting diet, while 27 per cent chose the Mediterranean and 18 per cent the paleo.

The aim of the research was to examine how effective all three diets were in a "real world" setting, where participants self-selected which diet they wished to follow, without any ongoing support from a dietitian.

Dr Roy says the evidence shows that for some people the Mediterranean, fasting or paleo (Paleolithic) diets can be "healthful, beneficial ways to eat".

She said: "This work supports the idea that there isn't a single 'right' diet - there are a range of options that may suit different people and be effective.

"In this study, people were given dietary guidelines at the start and then continued with their diets in the real world while living normally.

"About half of the participants were still following their diets after a year and had experienced improvements in markers of health.

"Like the Mediterranean diet, intermittent fasting and paleo diets can also be valid healthy eating approaches - the best diet is the one that includes healthy foods and suits the individual."

Dr Jospe said participants who were still following their diet at 12 months lost even more weight, showing the importance of choosing a diet that is sustainable.

She believes the results are relevant to the thousands of people following self-chosen diets with little supervision and indicates more realistic outcomes.