One of the best ways to keep track of what you are eating, and drinking is to keep a food diary. There are different phone apps you can use such as MyFitnessPal. With MyFitnessPal you set up a profile which includes your current body weight, what you want to achieve and how much exercise you complete each day. You then enter everything you have eaten and had to drink in exact amounts. It will then tell you how many kilocalories you have taken in, how many you have burned and the amount of protein, carbohydrates and fat you have had that day. If you are honest with it, you will likely find that you have eaten more then you think. You might not think that two biscuits with a cup of tea or coffee is anything to worry about, however if you have four cups of tea or coffee a day, and you have two biscuits with each one it will add up to half a packet of biscuits a day.
Another way of keeping a food diary is to simply keep a note book and write down what you have had to eat and drink. This is the version I prefer as it gives you the opportunity to write down how you feel after each meal. Did you like what you had, did it make you feel energised or did it make you feel ill. If you have a medical condition such as Irritable Bowl Syndrome/ IBS it can help you to identify trigger foods or drinks. The main reason I prefer to keep a written food diary as opposed to a digital one is the fact that it provides a permeant copy. Digital copies are convenient however all it takes is for you to accidently press the delete button and all your records are lost. With a written version this problem is eliminated.