Extreme diet or crash diet, is a method to lose a significant amount of weight within a limited time period. But crash diets are not meant for long term weight loss plans. Since crash diets usually cut down on one or more food groups to reach a desired weight level, these diets skip out on important nutrients that your body needs.
The ways crash diets can affect your body include:
Dehydration: You realise you are losing weight after implementing the crash diet, but this is just an illusion. All the weight lost isn’t fat, but water. When you restrict calories, your body first burns glycogen—not fat, for energy. Glycogen is a form of carbohydrate stored in the muscles and liver, and water is attached to every gram of glycogen. So when your body burns glycogen, you end up losing water, which causes dehydration.
Unstable blood sugar: When your body doesn’t get a steady supply of fibre, fat, protein and carbohydrates, your insulin and blood sugar levels run amok. Some diets, such as the detox diet, can lead to type II diabetes.
Muscle break down: Energy comes from calories and restricting calories adversely affects your muscles. When you start losing weight, your body starts harnessing muscle proteins for energy. This leads to muscle loss and your physique deteriorates. For instance, liquid diets (that have low calories) cause rapid muscle loss and can lead to ventricular arrhythmias.
Slow metabolism: Your metabolic rate crashes automatically when you lose muscles. This implies that you burn less calories when you talk, exercise and walk. You start feeling sluggish, and even after you get back to your normal diet, your metabolism won’t change back to how it was before.
Malnutrition: A lot of crash diets recommend eating less than 700 calories a day, which will help you lose weight, but it harms your body. The body needs calories, since they are an important energy source. Soon your body adapts to the lack of calories and becomes malnourished.
Intellectual problems: Some crash diets cut down carbohydrate consumption, and this ends up affecting your brain. The brain needs carbs to function properly. So, when there is a severe carbohydrate deficiency, the level of corticosterone (the stress hormone) increases in your brain, making you vulnerable to stress, depression and binge-eating behaviours. If you wish to discuss about any specific problem, you can consult a dietitian-nutritionist and ask a free question.