Research

Hormonal

Higher white blood cell (WBC) counts in obese individuals are largely mediated by elevated fasting plasma leptin concentrations, which stimulate haemopoietic stem cell proliferation.

If you are obese, your body produces more leptin, which signals your bone marrow to produce more white blood cells. This is a normal physiological response to higher body fat levels, not necessarily a sign of infection or disease. Understanding this link helps contextualize lab results in the context of body composition.

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In summary, the results of this study have demonstrated that the correlation between the WBC count and percent body fat in Pima Indians is largely explained by fasting plasma leptin concentrations. These findings, together with the recent demonstration that leptin directly stimulates haemopoiesis, suggest that higher WBC counts in otherwise healthy obese individuals may be due, in part, to the stimulatory effects of leptin on haemopoietic cells.
Charlton A. Wilson et al. · British Journal of Haematology · 1997

Why this rating

Observational study with strong statistical correlation (r=0.44, p=0.0001) and mechanistic support from cited in vitro/in vivo studies, but causality in humans is inferred rather than directly tested via intervention.

Source

Relationship of the white blood cell count to body fat: role of leptin

Charlton A. Wilson et al. · British Journal of Haematology · 1997

DOI 10.1046/j.1365-2141.1997.3873201.x

cross_sectional · n=117Cited 61×
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DOI resolved against Crossref · corpus check 2026-06-10

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