When you are starting any new behavior or new goal it is important to take an accurate picture of where you are currently at. It is impossible to see progress or change if you don’t know where you started from.
This means that you should either have another person do measurements for you, or accurately record your data without trying to fudge the numbers. Additionally, when recording your meals/calories, self-reporting will not work unless it is accurate. (“I think I ate…” doesn’t help anyone.)
You can keep an app on your phone to track your meals or your exercise or you can employ a wrist monitoring device such as a Fitbit or Apple Watch. Alternatively, you can write things down by hand in a paper journal including a nutrition log. The important part of this is just to consistently record how you are doing and you can see your accurate behavior.
Just like a bank may mention odd spending behavior, you should also notice when you are eating unhealthy foods and why you are eating them. Is it because you are hungry and are choosing wrong? Or is it out of comfort? Is it out of social obligation? (There are a multitude of reasons…just write them down and see where it takes you.)
At the end of a week, look at how you did and chart your activity week by week. It may not seem like a massive success to lose 1 lb a month, but at the end of the year, you have dropped 12 lbs and may feel a hundred times better than you felt in the beginning of the year.