Dietary sugars and healthSymposium Presentation
Sugars have replaced fat as the dominant public health concern in nutrition, sparking numerous debates. These issues have largely been driven by low-quality scientific evidence (e.g., ecological studies) linking increased intake of sugars with increased obesity and diabetes rates, along with animal models and select human trials that overfed sugars to levels of exposure that far exceed actual intakes.
To address the uncertainties in the evidence, we and others have conducted a series of systematic reviews and meta-analyses of the highest level of evidence taken from prospective cohort studies and controlled feeding trials. Although large prospective cohorts have shown a significant positive association of sugary beverages with incident obesity, diabetes, heart disease, and stroke, these associations are only seen when comparing the highest with the lowest levels of exposure. These associations do not hold true at moderate levels of intake for sugary beverages or at any level of intake when modeling total sugars. Sugars only contribute to weight gain and its downstream metabolic disturbances (raised blood lipids, uric acid level, blood sugar, insulin, and markers of fatty liver) insofar as they contribute to excess calories.
Moreover, as is the case with saturated fat, it is important to consider the whole food and not just isolated nutrients as we consume foods, not nutrients. In the case of milk products that contain added sugars (such as chocolate milk and sweetened yogurt), there are no adverse effects and, in fact, beneficial effects such as improvements in diet quality are seen.
Therefore, attention needs to remain focused on reducing overconsumption of all highly caloric foods, including those that contain sugar and, more importantly, to consider whole foods and dietary patterns rather than singling out individual nutrients when developing public health guidelines.