Naturally, these people tend to overlook their own mistakes and fail to understand what prevents them from losing weight. The human brain displays a remarkable ability of ignoring the things it does not want to face, so it's not hard to understand why some people eat all manner of things and still claim they haven't touched anything but salad for a whole week.
But there are ways of working around these problems and if you don't want to become one of these people, then you should stick to these pointers. Their purpose is to make eating a conscious act in order to avoid giving in to compulsions and temptations.
The easiest thing to do is to carry around a notebook and a pen and to write down everything you eat. And I mean every little thing. Have you finished that half a slice of pizza that your partner couldn't eat anymore? Write it down. At the end of the day look over the list and you'll be surprised at how many things you actually eat on a regular basis.
Since eating and drinking are, for the most part, acts that bypass rational thinking you should try to bring them out of the twilight zone. So every time you reach out for a drink or some food, stop and ask yourself "Why am I doing this?". You may be thirsty, hungry, bored, lonely, depressed, tired or stressed, but out of this list of reasons only thirst and hunger are legitimate. Put the bottle down if you're not thirsty. Put the food back on the shelf or on the table if you're not hungry. Do you crave sweets because you're tired? Get some sleep instead. Do you feel the need to eat because you're lonely and depressed? Go to the cinema or visit a friend. Read a book, watch a movie or listen to some music. There are options.
Never starve yourself. This is one of the big mistakes in dieting. Unless you have enough willpower to qualify for Nietzsche's Overman status you will break down sooner or later and eat the first thing that you can get your hands on. Such as snacks or fast food. Starvation also makes the body go into power save mode by limiting your energy levels and hanging on to the existing fat. The body makes no difference between dieting and actual starvation and will behave as if in danger. Therefore you must eat three meals a day, plus snacks consisting of fruit and vegetables. This is the best way to lose weight.
Don't try to banish your favorite foods completely because you will only sap your own willingness to stick to a diet. The key to dieting is moderation, not denial. Do you like ice cream? Well, have a couple of spoonfuls of ice cream every Sunday. Take a break from whatever it is you're doing and enjoy this special treat. Don't feel like you're cheating on the diet and keep any guilt pangs away. You're just dieting, not preparing for admission to a convent or monastery. So have a bit of forbidden food every five days or so and enjoy the moment.
And, of course, you must exercise. If you're not used to exercising and are a bit scared of all the effort and sweating, then start small. There's no need to rush into hour-long training sessions. Five minutes per day will do for starters. Get a treadmill and a pair of dumbbells and make your own schedule. Two minutes and a half of running and two minutes and half of curls. Every week increase the time spent exercising by another five minutes and add new exercises. Your goal should be to spend at least 30 minutes every day working out your body. Sixty minutes is even better, but it will come in time. It's OK to start small.