4. Discussion
obesity, glucose intolerance, T2D, weight gain, weight loss
OBESITY, GLUCOSE INTOLERANCE, SECONDARY
In this 3-year longitudinal analysis of individuals at high risk of T2D, higher added sugars intake predicted increasing body fat but was not associated with markers of glucose metabolism. In contrast, higher GI was associated with an increased waist circumference and glucose intolerance in the Sydney and Helsinki group. Interestingly, these trends were not seen with total sugars or free sugars intake, which were associated with improvements in glucose metabolism and were not linked with IBF. This may reflect other components in the food matrix or the type of sugar (glucose, fructose, sucrose, lactose) present.Anecdotally, many health professionals assume that added sugars increase the risk of developing T2D. However, average amounts of added sugars intake have either no relationship to incident T2D [In contrast to total carbohydrates and added sugars, many observational studies suggest that GI is a predictor of the development of T2D [In contrast to T2D, excessive consumption of sweetened drinks, and to a lesser extent sweetened foods, is widely acknowledged to have a role in the promotion of weight gain in prospective and experimental studies [The beneficial association between There are notable strengths of the present study. First, we provide new evidence of the associations between dietary sugars and health markers during longer-term weight loss maintenance, which is more likely to address a life-long issue, particularly for individuals with obesity and increased susceptibility to T2D. Few studies of weight loss maintenance and weight regain have been undertaken and rarely for as long as 3 years. Secondly, unlike some studies with fixed energy content, we determined the associations in a free-living context and an ad libitum diet. Thirdly, because diet and health markers were measured regularly over 3 years, we were able to leverage multiple, longitudinal, real-time data. This large dataset allowed adjustments for multiple confounders. We investigated the role of three types or sources of sugars (added, free and total) as well as multiple outcome indices for both glucose metabolism and body fatness after a period of rapid weight loss. Finally, the findings may be more generalizable because three different countries, albeit similar in terms of economy and food culture, were represented.Several limitations should also be noted. The GI and dietary sugars intakes were calculated from self-reported weighed 4-day food diaries in individuals whose added sugars intake was relatively low (4.2% ± 2.9% of total energy compared to 9.0% ± 7.5% of total energy reported in the Australian population based on national survey data for this age group) [In conclusion, this secondary analysis of a 3-year weight loss maintenance intervention found evidence that a higher intake of added sugars and a higher dietary GI was associated with increased body fat or waist circumference. In contrast, only GI was an independent predictor of worsening glucose status. Paradoxically, total and free sugar intakes were associated with improved glucose metabolism. Taken together, the findings from this particular study population add to the increasing body of evidence that the glycaemic index of foods and hence fluctuations in postprandial glycaemia may be more associated with increased future risk of T2D than added or free sugars intake. 