I'm also from a family with low blood pressure. And sugar is a great trick when it falls down even further. It also help me to study longer but it is hard to strick the right balance with extra-energy and reduced concentration.
McDs is packed with sugar. I quit eating mcds out of spite for 2 months and when i finally gave in and had em again i thought i was gonna have a heart attack. Then the stomach ache hit. Shit hardly counts as food. Anyway I think i either was used to their poison before or i never noticed the cramps, cuz it's happened every (scant) time I've eaten em since.
I don't think McDonald's is as bad as Burger King. I had a whopper and the bun made it actually taste sweet. Like a burger wrapped in a glazed donut or something. They're putting a ridiculous amount of sugar in those buns.
I hate MacDonald fries. They are soft and not crispy at all. I buy fries at store because achieving the crisp from scratch required cooking twice and I don't want to deal with that but I find out that most of stores sell now MacDo style of fries and I hate it.