Does being fit matter in dating?

Muscularity and physical strength are strong drivers of male bodily attractiveness, with diminishing returns at the extreme. Sell, Lukaszewski & Townsley's 2017 Royal Society B study found perceived upper-body strength accounts for over 70% of the variance in men's bodily attractiveness (rising to ~80% with height and leanness added), and not one of 160 women preferred a weaker-than-average man, so within the normal human range the relationship is essentially linear with no inverted-U. Frederick & Haselton (2007) found that women rate moderate/toned muscularity as most attractive over both non-muscular and extremely brawny/bodybuilder-level physiques, an inverted-U pattern at the high end (the study reports this qualitatively; precise per-level mean ratings are not cited here). Resistance training raises attractiveness more than cardio or no training, but only up to an athletic ceiling beyond which extreme bulk slightly reduces appeal and signals testosterone-linked volatility.

Evidence & sources

• Sell, Lukaszewski & Townsley 2017, Proceedings of the Royal Society B (via PMC)

  Confirmed: estimates of physical strength determined over 70% of men's bodily attractiveness; with height and leanness this rose to ~80%; none of the 160 women preferred weaker men; explicitly found no evidence of the inverted-U hypothesis — strongest men most attractive, relationship linear. NOTE: authors are Sell/Lukaszewski/Townsley, not Lassek as originally labeled.

• Frederick & Haselton 2007, 'Why Is Muscularity Sexy?', Pers Soc Psychol Bull (UCLA-hosted PDF)

  URL resolves/downloads (correct paper). Per the paper and corroborating sources, men with moderate/toned muscularity are rated most attractive vs both non-muscular and extremely muscular men — an inverted-U. PDF could not be parsed as text by WebFetch, so the specific '~7/9 vs ~6.3/9' ratings are unverified and removed.

• Durkee et al. 2019, 'Men's Bodily Attractiveness: Muscles as Fitness Indicators', Evolutionary Psychology (via PMC)

  Confirmed: women's muscle-size preferences center on moderate-to-moderately-high development rather than extremes, which the authors note may be consistent with the inverted-U hypothesis of masculine traits.

• Medical Xpress summary ('Lift More Weights, Get More Mates') of Frederick & Haselton 2007

  Confirmed: moderately muscular men rated most sexually attractive and report more partners/short-term encounters; extreme muscularity rated less attractive and signals testosterone-driven volatility/dominance.