Fat was the food villain these past few decades but sugar is quickly muscling in to take its place. As rates of sugar-related disorders such as diabetes, obesity and heart disease climb, many experts believe that when Americans rid themselves of fat, they simply replaced it with sugar in all its forms.
But proving that the rise of the chronic diseases was actually linked to higher sugar consumption is a challenge. Dr. Robert Lustig, from the department of pediatrics at the University of California, San Francisco, who has made a name for himself publishing books and research addressing the question of sugars effects on the body, wanted clearer answers. Now, in a paper published Tuesday, he and his colleagues believe they have come up with the definitive evidence that sugar, as Lustig says, is toxic.
In most lab studies, the doses of sugar that scientists test are quite high; they want to see what the effect is quickly and, depending on the research, they may not have time to wait to study the more gradual effects that might emerge. And in studies where people reduce the amount of sugar they eat, for instance, those people end up eating fewer calories overall, so its difficult to know whether any changes are due to the removal of sugar or to the drop in calories.
Lustig and his colleagues think theyve produced the hard and fast data that sugar is toxic irrespective of its calories and irrespective of weight.
Up until now, there have been a lot of correlation studies linking sugar and metabolic syndrome, says Lustig. This is causation.
Lustigs confidence comes from the unique study, described in Obesity, of 43 Hispanic or African-American children aged eight to 18 years old. He collected detailed food questionnaires from each of the adolescents to get an idea of the average amount of calories they ate per day, then designed a special menu for each of them for nine days that matched the total numbers of calories they would normally eat. The only difference in the nine-day diet was that most of the sugar the children ate was replaced by starch the overall number of calories remained the same. The children weighed themselves daily, and if they were losing weight, they were told to eat more of the provided food in order to keep their weight the same throughout the study.
Everything got better, says Lustig. Some of the children went from being insulin resistant, a precursor state to developing diabetes, in which the bodys insulin levels can no longer keep up with the pace of breaking down sugar thats coming in from the diet, to insulin sensitive.