Im going to start by saying something that most people aren’t going to want to hear. The number one WORSTEST EVER IN THE UNIVERSE OF EVEREST WAY to lose weight is FAST! Yes! Losing weight fast is the absolute worst way to lose weight. This is usually done by dieting with extreme caloric deficits. What this means is, you are eating way less calories than you are burning. 
 For example:A 140lb woman that exercises 3-5 times per week will burn about 1600-1700 calories per day. If this woman only consumes 1100 calories or under per day, she is putting herself in the danger zone. She is setting herself up for failure and a host of medical and psychological problems.

Problems caused by “extreme dieting”
 Atrophy: This includes hair, bone, and muscle loss. When you are attempting to lose fat and to change the composition of your body, the last thing you want is to lose muscle. Muscle is your body’s number one fat burning tool. So the more muscle you lose the more you decrease your body’s ability to burn fat which leads to the infamous “Plateau”. Which really isn’t a natural plateau (because fat loss plateau’s happen even if you prevent muscle loss). With extreme dieting you essentially run your body into a fat burning dead end.
 Metabolic damage: And this term is thrown around loosely but let me try to break down what it means. When you eat calorie amounts substantially below the amount that your body needs to function optimally, for extended periods of time something bad happens. After a while your body gets used to functioning with just  limited amount of calories (our body does this by default as a survival mechanism) and then the amount of calories that our body maintains its weight at decreases!
 For example:If I can maintain my weight of 175 lbs eating 2000 calories a day and I go on a long term diet (Maybe 6 months to a year) eating 1100 calories a day, eventually my body stops losing weight at this caloric intake level and begins to simply maintain my weight.  So now my maintenance calorie level is decreased to around 1400-1500 when I should be able to lose body fat eating this amount of calories. I Hope I explained that well.
 Binging!! : You’re essentially starving your body and your mind of important nutrients. Which will eventually make you crazy? Your discipline stores will deplete (we do only have a certain amount of discipline. It is NOT an unlimited resource) and you will give in the minute your aunt pulls that chocolate cake out of the refrigerator. You won’t be able to have one small piece. You’re body’s going to be craving calories and sugar so bad that you are not going to be able to help but over indulge. Next thing you know you look up and you ate half of a chocolate cake! Then comes the regret and the discouragement, and the skipping of the gym etc… its a very slippery slope and an extremely vicious cycle. But this is all preventable.
 Lack of energy and focus:  You are what you eat right? So it is very simple math, if you don’t eat enough, you will not be enough.
 The number one tool to approach your weight-loss journey with is PATIENCE. Against what’s popularly advertised, it is a slow process that requires realistic adjustments to your lifestyle, patience for trial and error.