Measuring sweetness of total diet in future research would help advance evidence-based dietary recommendations
- Current evidence does not support the hypothesis that reducing exposure to sweet taste may reduce “sweet tooth” and, in turn, the intake of added sugars and calories.
- In a perspective, experts call for agreement on an optimal approach for measuring sweetness of the total diet.
- If consensus sweetness measures were developed, new science could address the role of dietary sweetness in the diet and in health to inform evidence-based dietary recommendations.
In a perspective published in Advances in Nutrition in late 20201, eleven nutrition and sensory science researchers reviewed existing measures of sweetness in foods and beverages to better understand the role of sweet taste in the diet and in health. The review provides an overview of available sensory techniques and discusses recent efforts to measure the sweetness of whole diets across countries and cultures. An important contribution to future research is a proposed future direction for improving methods for measuring sweetness in an effort to base dietary recommendations around sweetness on rigorous science.
With sugar reduction being a key objective of nutrition recommendations worldwide, some organisations recommend reducing the consumption of sweet-tasting foods and beverages, regardless of the source of the sweetness (i.e., with or without calories). While there is no evidence to support this recommendation, the underlying hypothesis is that reduced exposure to sweetness would lead to reduced preferences for sweet-tasting food; in turn, reduced preferences would lead to lower sugar intake, and ultimately reduced consumption would decrease calorie intake and assist in weight loss. However, current evidence summarised in a recent systematic review does not support the links in this presumed causal chain.2
In their systematic review of published data exploring the impact of dietary exposure to sweetness on the subsequent preference and intake of sweet foods and beverages in the diet, Appleton et al found no consistent support for a relation between sweet taste exposure and subsequent preferences or sweet food intake.2 Also, a literature review by Public Health England reached a similar conclusion in 2015.3 Thus, evidence to support the assumption that lower sweetness in the diet would lead to decreased calorie intake and weight loss is lacking.
The experts who contributed to this review concluded that, in order to address unresolved research questions regarding dietary sweetness and health outcomes, a generally agreed-upon measure of sweetness is needed. An effective measure that would capture the sweetness of an entire diet or dietary pattern, not merely the sweetness of specific foods. While challenging, some researchers have already made efforts to develop such measures. Currently, three studies have developed taste databases that measured the sweetness intensity of foods and whole diets in four countries: Australia, France, Netherlands and Malaysia.4-6 This method can contribute important insight on the role of sweetness in health. For example, by analysing taste dietary patterns in the Netherlands, it was found that people of different body weights (normal, overweight and obesity) tend to have similar calorie intake from sweet foods.7
The experts concluded on priorities in future research.1 If consensus over sensory approach for measuring the sweetness of the whole diet in settings other than the laboratory could be developed, researchers could combine data from different studies and conduct new science to examine the validity of currently unsubstantiated recommendations calling for sweetness reduction and to vigorously address unresolved research questions regarding the role of dietary sweetness in the diet and in health. This could help advance evidence-based dietary advice.
This review was supported by ILSI [International Life Sciences Institute] North America and, in part, includes information shared in a meeting, “Think Tank: Measuring Sweetness in Foods, Beverages and Diets,” organised by ILSI North America, held on 12 December 2019 in Washington, DC.