Research
Macro partitioning
US adults significantly improved diet quality between 1999 and 2016 by decreasing low-quality carbohydrates (primarily added sugars) and increasing high-quality carbohydrates (primarily whole grains), plant protein, and polyunsaturated fats.
Focus on swapping low-quality carbohydrates for high-quality ones. Specifically, reduce added sugars and increase intake of whole grains, plant-based proteins (like nuts and whole grains), and polyunsaturated fats. While overall diet quality has improved, these specific swaps are the key drivers of that improvement.
StrongSupportsVERY_HIGH confidence
From 1999 to 2016, US adults experienced a significant decrease in percentage of energy intake from low-quality carbohydrates and significant increases in percentage of energy intake from high-quality carbohydrates, plant protein, and polyunsaturated fat.
Why this rating
Large, nationally representative sample (n=43,996) using serial cross-sectional data over 18 years.
Source
Trends in Dietary Carbohydrate, Protein, and Fat Intake and Diet Quality Among US Adults, 1999-2016
Zhilei Shan et al. · JAMA · 2019
DOI 10.1001/jama.2019.13771
cross_sectional · n=43996Cited 567×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
More from this paper
- Despite improvements, US adults continue to consume disproportionately high energy from low-quality carbohydrates and saturated fat remains above recommended levels.Strong
- Socioeconomic disparities exist in dietary improvements, with higher-income and higher-education individuals showing greater improvements in macronutrient composition and diet quality.Good
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