Pick your diet - high carb, low carb, Paleo or South Beach - but in the long term most don't work. New research has found that all diets work as long as you stick to them. But after a year of starting any diet, most people have only shed a couple of kilograms.Bariatric Medical Institute professor Yoni Freedhoff and metabolism researcher Dr Kevin Hall, writing in Lancet Obesity, suggested that scientists should stop wasting money on "diet wars" and try to get overweight people to stick to diets for the long term."Even the most divergent of diets seem capable of affecting a degree of short-term success, with some diets perhaps leading to marginally greater losses than others over periods of several months."But since obesity is a chronic condition, it is the long term that matters. An effective diet for clinical weight management needs to be established over timescales of years to decades."A Journal of American Medicine 2014 analysis of different diets showed most people lost about 8kg after six months of starting a diet, but within a year dieters had put a couple of kilograms back on.For diets to work, scientists believe they need to understand the complex reasons why people eat.South African dietician Tabitha Hume agreed: "Eating holds much more function than merely providing nutrients to the body. It has an overwhelmingly huge emotional component that cannot be disregarded. It is a very complex process. For instance, if someone has even mild depression, he or she will choose foods that stimulate serotonin production, such as crisps, pastries, chocolates or sweets. This will make them fat and this self-medication will not respond to 'willpower'." This is why dieticians were needed, she said."Our job is to establish the cause of overweight and then treat the cause individually and within the constraints of each individual - including finances, culture, food availability, time constraints and psychological implications."But sports scientist Tim Noakes is sticking to promoting his low- carb diet - even after reading the Lancet article."Metabolically, the low-carb diet produces outcomes that cannot be achieved on a low-fat diet. This is because the treatment for insulin resistance - which is the real problem that we face in society - is a low-carbohydrate diet. Feeding people with insulin resistance a diet with even a moderate carbohydrate content will not produce a good result in the long term."Noakes said it was easy to comply with his low-carb diet "because it takes away hunger and this makes eating an absolute pleasure"...