Library.

“Obesity in men lowers testosterone levels and thereby reduces criminal perpetration rates.”

The proposed reduction in criminal perpetration is unsupported. Obesity can lower testosterone in men, but no evidence demonstrates that this hormonal effect causes less offending. The only cited longitudinal study examining obesity and later criminal outcomes instead reported higher adult felony-conviction prevalence among people with pediatric obesity, although it did not isolate men or test testosterone as a mediator.

“Obesity makes men less violent because it lowers testosterone levels.”

The proposed causal explanation is unsupported. Obesity is associated with lower testosterone in men, but research does not show that this makes men less violent; testosterone’s relationship with human aggression is weak and does not establish causation. Several behavioral studies instead associate higher body mass with greater aggression or externalizing behavior, while limited arrest data cannot prove the claimed mechanism.

“Low testosterone levels can cause obesity in men.”

Low testosterone can contribute to fat gain and, in some men, to obesity. Mechanistic, longitudinal, and clinical evidence indicates that testosterone deficiency promotes adiposity and visceral fat accumulation, especially in more severe hypogonadal states. However, the relationship is bidirectional, and obesity is more often a cause of low testosterone than the primary result of it.

“Obesity in men causes androgen deficiency.”

Obesity does appear to causally lower testosterone in men, and severe obesity can lead to genuine obesity-related hypogonadism. But the claim is too broad as stated: many obese men have lower total testosterone without true clinical androgen deficiency, because free testosterone may remain normal and the state is often functional and reversible. The evidence supports a real link, not the blanket formulation.

“Obesity in women causes estrogen deficiency.”

The evidence does not support the broad claim as stated. In some premenopausal contexts, obesity is associated with lower estradiol or altered hormone signaling, but after menopause obesity commonly raises estrogen levels because adipose tissue produces estrogen. That means the relationship is bidirectional and depends heavily on menopausal status, so describing obesity in women generally as causing estrogen deficiency is materially misleading.

“Obesity is a causal risk factor for developing cancer in humans.”

Evidence from major health agencies, large cohort meta-analyses, mechanistic experiments, and weight-loss interventions consistently shows that excess body fat contributes to the development of multiple common cancers in humans. While strength of evidence varies by cancer site and some trials of modest lifestyle weight loss are inconclusive, the overall scientific consensus classifies obesity as a causal risk factor for cancer rather than a mere correlation.

“Individuals with both excess belly fat and low muscle mass (sarcopenic obesity) have an 83% higher risk of death compared to individuals with neither condition.”

The 83% figure comes from one 2024 cohort study of adults aged 50+ using a specific proxy definition of sarcopenic obesity. However, the claim presents this as a general fact. Larger meta-analyses pooling over 50,000 participants across dozens of studies consistently find a smaller increased mortality risk of roughly 21–24%. While sarcopenic obesity is genuinely associated with higher death risk, the 83% figure is a population-specific estimate, not a broadly established benchmark.