Balanced carbohydrate ratios are associated with improved diet quality in Australia: A nationally representative cross-sectional study

BACKGROUND: Carbohydrate quality influences major health outcomes; however, the best criteria to assess carbohydrate quality remain unknown.

OBJECTIVE: The objectives were to: i) evaluate whether a diet that meets a carbohydrate ratio (simple, modified or dual ratio) is associated with higher nutrient intakes and diet quality, and ii) model the impact of substituting carbohydrate foods that meet the proposed ratios in place of foods that do not, on nutrient intakes.

DESIGN: A secondary analysis of cross-sectional data from the 2011-12 Australian National Nutrition and Physical Activity Survey.

PARTICIPANTS/SETTING: National data from participants aged 2 years and older (n = 12,153).

MAIN OUTCOME MEASURES: Ratios were defined as (i) simple ratio, 10:1 (10g carbohydrate:≥1g dietary fiber); (ii) modified ratio, 10:1:2 (10g carbohydrate:≥1g dietary fiber:≤2g free sugars); and (iii) dual ratio, 10:1 & 1:2 (10g carbohydrate:≥1g dietary fiber & ≤2g free sugars per 1g dietary fiber). Ratios were compared to nutrient intakes obtained via automated multiple-pass 24-hour dietary recall and diet quality calculated using the Australian Healthy Eating Index.

STATISTICAL ANALYSES PERFORMED: Substitution dietary modelling was performed. Data were analyzed using paired and independent sample t-tests.

RESULTS: Ratio adherence was highest for simple (50.2% adults; 28.6% children), followed by dual (40.6% adults; 21.7% children), then modified (32.7% adults; 18.6% children) ratios. Participants who met any ratio reported higher nutrient intake and diet quality compared to those who failed to meet the respective ratio (P < .001 for all), with the greatest nutrient intakes found for those who met modified or dual ratios. Dietary modelling improved nutrient intakes for all ratios, with the greatest improvement found for the dual ratio.

CONCLUSIONS: All carbohydrate ratios were associated with higher diet quality, with a free sugars constraint in the dual ratio providing the greatest improvements.