Keep a food diary for a couple of days
This maybe boring but it's quite easy.
And - so long as you're honest with yourself and don't quietly "forget" to write down all the crisps and chocolate bars and cans of pop and other quick drinks - it's probably the easiest place to spot where you can cut the calories and almost not notice.
Most people who do this find that one or two things almost leap off the page at them.
It could be the two or three teaspoons of sugar in every cup of tea or coffee.
It could be the "essential" chocolate bar or cream cake (or both).
Or it could just be that all the portions are super-sized at an absolute minimum.
And those are the places to start. Because it's fairly easy to either downsize some of the portions you're eating or reduce your intake of other things like sugar or take one less drink after work or whatever.
Take a look for the "wrong" calories
These could be empty calories like the ones found in beer and other alcohol.
Or they could be hidden sugar - read up on all the words on the label that sneaky manufacturers use to disguise just how much sugar they're adding. Sugar, fructose, sucrose, dextrose, corn syrup, etc. etc, etc.
And if it's sugars don't think that switching to diet drinks will work. Our bodies haven't got a clue about saccharin or any of the other artificial sweeteners so we react as though they're real sugar. With consequences that aren't exactly favourable for our health.
Fat isn't necessarily bad - it depends which studies you read whether it is or not - but it's probably a good idea to reduce it in your diet. Which could be as simple as switching to lower fat milk, not adding as much milk, not pouring on extra cream, using leaner meat or even using a non-stick pan to reduce the amount of fat you use to cook.
If you're not madly overweight, doing just those few things could set you on the path to being a new, lighter, you with almost no effort.
If you're quite a few pounds heavier than you should be, take a closer look at portion size and calorie counts. Preferably before your doctor gives you an ultimatum.
The good news is that small adjustments to your diet can be very easy to make and can have a lasting, positive, impact.
So resolve to at least look at them and ideally actually do something about it!