There is a major chance that crash diets may result in rapid initial weight loss but may have a negative effect on long-term health and diet compliance. Losing too much weight too quickly can cause a bunch of problems you may not have seen coming. The most common ways people try to lose weight: Starvation diets Consumption of diet pills or supplement Opting for a very low calorie diets Over exercising Here are the major reasons you may want to take it at a more reasonable pace: You may also end up malnourished: You might not be getting the vitamins you need. Not every quick weight loss case will get this far. But a serious danger of taking your crash diet to an extreme is malnutrition. This can have serious health consequences for you. Fast weight loss can dehydrate you: Making radical changes to your eating habits that involve restricting caloric intake, the first thing to go is water weight. It's not a major issue as long as you're making the effort to stay hydrated but if you're not taking care of your hydration needs in the name of keeping your weight down, that could be a big. You could be tired all the time: It could cause fatigue and the nutritional deficiencies could also see you develop anemia. Those deficiencies may have a direct effect on whether you feel awake and alert after a good night's sleep or whether you feel extremely fatigued. You might have uncomfortable digestive problems: A lot of us probably think that we spend enough time in the bathroom as we want to do. However, if the weight loss is rapid, you can experience nausea, diarrhea, constipation, and abdominal pain. You could also seriously slow down your metabolism: A slower metabolism burns fewer calories per day, which in turn makes it easier for you to gain weight on a lesser amount of food. Not just that, but your sleep cycle could also suffer as a result of your decreased metabolism.