Life-history theory predicts that nutrition influences lifespan owing to trade-offs between allocating resources to reproduction, growth and repair. Despite occasional reports that early diet has strong effects on lifespan, it is unclear whether this prediction is generally supported by empirical studies. We conducted a meta-analysis across experimental studies manipulating pre- or post-natal diet and measuring longevity. We found no overall effect of early diet on lifespan. We used meta-regression, considering moderator variables based on experimental and life-history traits, to test predictions regarding the strength and direction of effects that could lead to positive or negative effects. Pre-natal diet manipulations reduced lifespan, but there were no effects of later diet, manipulation type, development mode, or sex. The results are consistent with the prediction that early diet restriction disrupts growth and results in increased somatic damage, which incurs lifespan costs. Our findings raise a cautionary note, however, for placing too strong an emphasis on early diet effects on lifespan and highlight limitations of measuring these effects under laboratory conditions.