&gt; Why is it that some people, regardless of how much they eat and how little they exercise, never put on weight? That, to me, is the elephant in the room.<p>This is another problem that people can and have solved. You simply aren&#x27;t eating as much as you think, so you take meticulous track of your caloric intake, and once you realize you eat a lot less than you thought, force yourself to eat X 100s of calories over normal intake per day. This is likely a quantity of food that causes physical discomfort initially, but it works.<p>Ignoring issues like Crohn&#x27;s, &quot;I can&#x27;t gain weight&quot; is just as much an excuse as &quot;I can&#x27;t lose weight&quot;, although perhaps more socially accepted due to body type voodoo.