It can be difficult to squeeze in exercise when you lead a busy life, having to look after your family and work long hours, but you need to make regular exercise and eating well a priority for the benefit your health. It isn't something you should keep putting off, as at some point your lack of fitness and poor diet will begin to affect your health. You therefore need to consider where you can make more room in your schedule for physical activity and how to adopt a healthier eating plan so that you can remain healthy for as long as possible for your family's sake as well as your own.
Obviously how you keep fit at work depends on the kind of job you are doing. Perhaps you are already engaged in a physically demanding job, particularly if you are expected to be on your feet all day, moving from place to place and lifting heavy items. Even if you do have an active job, though, you still need to watch what you eat since physical exertion doesn't mean you can eat whatever and however much you want to. You can still end up consuming more calories than you expend, making it more likely you gain weight, whilst eating a diet consisting mainly of junk food can lead you to feel lethargic, have difficulty concentrating, as well as mood swings. You may also be clogging your arteries and be at greater risk of heart disease later down the road.
If you have an office job, work in a shop or any other kind of work which doesn't require you to expend a lot of energy you need to look for ways to become more energetic and to make the activities that you do count for more in terms of the calories you burn. It has been suggested that simply fidgeting can help you maintain a healthy weight. So, get tapping your feet on the floor, drumming your fingers on the table, wandering around your floor whenever you have an opportunity, and stretching. They may only be little things but they do mean that you are not completely stationary.
Also, instead of using the lift to move between floors you could try walking more. Walking up and down stairs can be a good way to get fit, particularly if you put some effort into it, maybe even jogging up the stairs. Any opportunity you get to be on your feet rather than sitting down provides a way of burning more calories and getting fitter.
You shouldn't only think about how to get more active at work - there is always before and after work to consider. If you have to commute to work you have the perfect excuse to get more active, and thus fitter. You could walk or cycle there, or if it too far to cover the whole distance simply take public transport and get off a stop earlier than you need to, or you could take your car but park at a considerable distance away from your place of work.
There are ways to keep fit at work, but it does require you to look at things differently and to recognise the opportunity for physical activity in whatever activities you are engaged in.