Employees can't deduct ordinary commuting from your home, or meals taken before, during or after the workday. There is an exception if you are traveling but the litmus test there is that where you sleep that night is a significant distance from your home. There is also an exception for lunches which are bona-fide business meetings, but this is so widely abused that IRS has picayune rules to keep you from gaming that exception, and they can bite you at audit time.
Office space needs to be an exclusive room used only for office. As far as equipment, you can't deduct equipment that is dual-use -- work and also non-work (being a student is non-work unless it's an employer-required course). It needs to pass a "duck test" -- does it look, walk and quack like this is exclusively for work? That can be hard to do in tight quarters.
Suppose you're a draftsman and you own an expensive 42" plotter "for work". But your model railroad room is lined with intricate drawings of model trains obviously printed out on that same 42" plotter. Whoops.
Also, expensive equipment needs to be depreciated - you can't buy a $3000 PC and then boom, take $3000 off your taxes in year 1. Weird, I know.
Generally, if you are getting inventive about how to take deductions, IRS staff and Congress has already been inventive about catching that particular scheme.