It's pretty obviously the food since this problem only started with the invention of man made sugars and vegetable fats that form the basis of all processed and junk foods. Modern food addiction is very real, we didn't evolve eating more than a measly amount of carbohydrates. The endless hunger signals are partly due to the blood sugar spikes but it's also because modern foods are so nutritionally empty that the brain keeps sending hunger signals so long as its needs for certain amino acids and micronutrients are not met. This is why they keep eating and also why vegans are compelled to stuff their guts to the point of distention yet still feel hungry. To get 100g of complete amino acids from processed food would take an enormous amount of calories. If you put these people on nothing but meat eggs fish and water they would struggle with sugar withdrawals but after that they would start losing weight drastically without feeling hungry since the foods are so nutrient dense.