no comment on your second theory but your first theory is not exactly groundbreaking.

every person has a set point weight beyond which they do not gain weight even if they do not diet or exercise - this is simply the maximum amount of fat your body can hold. when you are at that point ( which varies by individual ) your body cannot regulate anything because to regulate it must have ability to increase and decrease fat stores as needed but when it's at max it can't increse and can't regulate - so it begins to take damage.

metabolic syndrome is simply an umbrella term for all sorts of bad shit associated with this downward spiral. metabolic syndrome doesn't imply what causes what - only that things like hypertension, large waist, high blood sugar and heart disease cluster together.

overeating is the cause. it causes the large waist. and that causes everything else.

that doesn't mean you can't be born with high blood pressure that is just there for no reason.

in MY case i only have high blood pressure when i am overweight - and it drops when i diet.