Apart from getting absolutely cranky and wanting to shoot everything in the line of fire, there are other side effects of not sleeping enough. The problems you ascribe to other things like bad food and cold weather are usually the result of not getting sleep for a good number of hours.
Ideally, an adult needs 7-8 hours of sound sleep in order to function efficiently the next day. But with the influx of Facebook, Instagram, Snapchat and other social media platforms, sleeping for 5 hours is considered to be a blessing.