As mentioned, eat less than you use.
There are some good web sites (often government run) that will have recommendations of how much energy in Kj's or Kcal's to eat per day depending on your age and level of 'usage'.
Then spend 5 mins just guesstimating what the food you eat really contains, sandwiches, pasta, meat, eggs etc and make an excel spreadsheet.
If you eat less (note: do still eat 3-5 meals per day) you will probably feel hungry for the first three weeks due smaller portion sizes but after this initial period you will feel quite full after a now normal sized meal.
Also, do start moving but try not to be too hard on yourself because you Will suck (or feel like you suck) at everything. Start with low impact stuff like swimming or fast pace walking.
Or... join the armed forces, that worked for me
Good luck man!