Sugar is getting an increasingly bad rap. Only last week, a leaked report by government advisory group Public Health England - which health secretary Jeremy Hunt initially tried to keep hushed - pinpointed sugar’s role in a soaring obesity crisis and proposed “a price increase of a minimum of 10%-20% on high-sugar products through the use of a tax or levy”. Meanwhile, on Monday 20 October, celebrity chef Jamie Oliver gave evidence to the Health Committee on childhood obesity about why a sugar tax should be slapped onto food and drink, despite previous opposition to the idea by some ministers, including Prime Minister David Cameron, who instead has indicated that measures such as a clampdown on advertising and marketing deals could form part of a childhood obesity strategy. Oliver has already added a sugar-levy to his restaurant chains, but has faced criticism for his apparent lack of understanding about the issue of obesity – especially within the different social classes. However, the celebrity chef’s grave concerns about the impact of sugar on the human body would appear to carry weight, with the suggestions from a new study that reducing sugar in diets even without cutting calories or losing weight can significantly boost health in less than 10 days. The study, featured in the journal Obesity, looked at obese children and discovered significant changes in lowering blood pressure and cholesterol in less than a fortnight. In total, 43 children aged 9 to 18 took part in the study at the University of California San Francisco Benioff Children's Hospital. All children participating in the study were obese with at least one other chronic disorder, such as high blood pressure. They were given 9 days of food prepared for them by the clinic and were weighed each day. The added sugar in their diet was cut back from 28% to 10%. In addition, the fructose – a type of sugar often advisable to limit – was reduced from 12% to 4% of their total calorie intake. Results clearly showed that the new meal plan given to the children resulted in major improvements to their health in a short duration. Diastolic blood pressure dropped by 5mm, levels of blood fats called triglycerides dropped by 33 points, LDL-cholesterol, also known as “bad” cholesterol, dropped by 10 points, and liver function tests improved. The diet overall stuck to the same fat, protein, carbohydrate, and calorie levels as their previous diets at home, but sugary food was replaced by starchy food such as turkey, hot dogs, crisps and pizza. The Scientists involved in the study state that sugar was “metabolically harmful not because of its calories” but due to the fact it is putting a lot of strain on the body. The study assessed potential impacts of limiting sugar on metabolic syndrome, a cluster of conditions that raise heart disease risk, stroke and Type 2 diabetes. Those with metabolic syndrome may find they have raised blood pressure, high blood glucose levels, excess body fat around the waist and unusual cholesterol levels. During the study, those children that did lose weight, were then given more low sugar foods to keep weight stable. Lead author, Dr Robert Lustig, said: “This study definitively shows that sugar is metabolically harmful not because of its calories or its effects on weight; rather sugar is metabolically harmful because it's sugar. “This internally controlled intervention study is a solid indication that sugar contributes to metabolic syndrome, and is the strongest evidence to date that the negative effects of sugar are not because of calories or obesity.” Jean-Marc Schwarz, senior author of the paper, added: "I have never seen results as striking or significant in our human studies. “After only nine days of fructose restriction, the results are dramatic and consistent from subject to subject.” “All of the surrogate measures of metabolic health got better, just by substituting starch for sugar in their processed food — all without changing calories or weight or exercise,” said Dr Lustig. “These findings support the idea that it is essential for parents to evaluate sugar intake and to be mindful of the health effects of what their children are consuming. “When we took the sugar out, the kids started responding to their satiety cues. “They told us it felt like so much more food, even though they were consuming the same number of calories as before, just with significantly less sugar. “Some said we were overwhelming them with food.” Dr Lustig said: "This study demonstrates that a calorie is not a calorie. “Where those calories come from determines where in the body they go.” “Sugar calories are the worst, because they turn to fat in the liver, driving insulin resistance, and driving risk for diabetes, heart, and liver disease. "This has enormous implications for the food industry, chronic disease, and health care costs." Dr Aseem Malhotra, a cardiologist and advisor to Action on Sugar, said: “It's time to abandon the outdated notion that a calorie is a calorie theory that continues to damage public health. This study provides further evidence that all calories do not have the same metabolic effects on the body with sugar calories being particularly harmful.” Tracy Parker, heart health dietitian at the British Heart Foundation, said: “This study is interesting, but we need more research to confirm these findings. Previous studies have suggested that eating too much added sugar increases a person’s risk of development of the various diseases, including cardiovascular disease, type 2 diabetes, hypertension and high cholesterol, because of the link with excess calorie intake leading to obesity.”