I did some research on this.  The death rate for anorexia (the deadliest mental disorder) for the high-risk group is actually lower than the death rate for 40+ BMI obese people.  So yes, being really fat is deadlier.  Plus epidemiologically speaking, anorexia is extremely rare (occuring in something like 0.01% of the population) whereas something like 10% of the American adult population is BMI 40 Obesity is much worse and more serious right now.  Anorexia is also serious, but it's used to discredit and distract from real facts about obesity and that's wrong.