Research
Macro partitioning
In humans, protein intake is a stronger determinant of serum IGF-1 levels than total calorie intake; reducing protein intake lowers IGF-1 even during calorie restriction.
If you are interested in lowering IGF-1 (potentially for cancer risk reduction or longevity), reducing your protein intake is more effective than just cutting calories. Try reducing protein to around 0.8-1.0 g/kg of body weight, ensuring you still get adequate calories and nutrients.
GoodSupportsHIGH confidence
In addition, our data provide evidence that protein intake is a key determinant of circulating IGF-1 levels in humans, and suggest that reduced protein intake may become an important component of anticancer and anti-aging dietary interventions.
Why this rating
Supported by cross-sectional data and a short-term intervention study with clear statistical significance.
Source
Long‐term effects of calorie or protein restriction on serum IGF‐1 and IGFBP‐3 concentration in humans
Luigi Fontana et al. · Aging Cell · 2008
DOI 10.1111/j.1474-9726.2008.00417.x
rct · n=94Cited 391×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
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