Since our environment, mood, etc. play their part in our brain chemistry and "brain genes" activation/deactivation (gene expression), this could mean that there is more to weight loss than sports and nutrition. IIRC the hypothalamus enacts control over our body via hormone production, meaning that a "hypothalamus problem" could hinder thyroid hormones or up cortisol production.

It fits well into the big picture - stress or stressful environment cause "bad" gene expressions in hypothalamus -> hormone imbalance -> metabolism lowered -> fat storage.

Perhaps the effect of our environment and wellbeing on our bodyweight is greater than one would have thought.