英语翻译As turns it out,those jitters you feel after eating a Mc

翻译：
事实上,你的紧张情绪并不是因为你在麦当劳吃了汉堡,而是因为你压力过大.
As turns it out可视作独立成分,译作“事实上”“最终表明”“后来发现”等即可；注意,你原句中的语序为倒装结构,即主语it在谓语动词turn的后面,而一般情况下是写为As it turns out,即正序结构.
those jitters you feel after eating a McDonald’s hamburger aren’t just because of the contents of the meal you eat为主系表结构.其中主语为jitters,后面的you feel after eating a McDonald’s hamburger 是其定语,说明了是在何种情况下产生的jitters；aren’t是系动词的否定式；just because of the contents of the meal you eat为表语,合起来本句说明了引起不适反应的虚假原因为你吃了什么.
接下来的一句说明了引起jitters的真正原因
it’s because of your brain getting stressed out.是因为你压力过大而引起的.此句也为一个主系表结构.because of your brain getting stressed out这个介词词组充当表语,说明了引起不适的原因为 your brain getting stressed out,即你大脑过度紧张.