Macro partitioning
Commercial protein bars in Brazil frequently overestimate their protein content by more than 20% compared to laboratory analysis, primarily due to non-protein nitrogen compounds being counted as protein by standard testing methods.
Do not blindly trust the protein number on the bar's label. This study found that 35% of bars had protein levels significantly higher than stated (overestimation). While this means you might get more protein than expected, it indicates poor quality control. If you are tracking macros precisely, assume the label is an estimate, not a guarantee, and prioritize brands with transparent third-party testing.
35% of the samples showed deviations greater than ±20%, indicating non-compliance with current labeling regulations. The discrepancies observed represented overestimations of the declared values, possibly influenced by the presence of non-protein nitrogen compounds.
Why this rating
The study uses a standard, validated chemical method (Kjeldahl) on a representative sample of 20 brands, though it is a cross-sectional snapshot.
Source
Avaliação do teor de proteínas e da conformidade de rotulagem em barras proteicas comercializadas como suplementos alimentares
Paulo Sérgio Marinelli et al. · Research Society and Development · 2025
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