Stop overeating, learn to drop the fork. I used to weigh nearly 300lbs. I currently weigh 170 at 5'11". Glandular problems resulting in the levels of obesity that we're seeing is exceedingly rare. It is a factor, but not a statistically significant one. The most crucial factor in obesity is overeating, and a complete lack of self control, period. If you're not physically active, realistically, you only need about 15-1700 calories per day, average. If you happen to engage in a lot of physically demanding sports, 20-2500, tops. As for animal obesity, corporate farms cage their animals, or coop them in environments where regular physical activity is severely hampered, pump them full of hormones, and overfeed them with cheap, quasinutritional filler food. Realistically, if you want to lose weight, east less grains, more fruits and vegetables, and avoid darker meats if possible. Sugary drinks aren't actually that bad, as sugar is never stored in the fat cells, and instead transcribed into the bloodstream (glucose reabsorption/reuptake).