What Happens When You Crash Diet?
Often times, quick weight loss goes hand in hand with crash dieting, but this isn't always the best solution. “Crash diets” are typically extremely low-calorie diets that require drastic measures - like eliminating multiple food groups, drinking only juice or soup for weeks, or fasting for multiple days to cut out as many calories as possible.
Very low calorie diets (VLCDs) are also used as treatment against obesity in some medical centres, but these programs are supervised by trained physicians, and not necessarily the right approach for everyone.
But starving yourself only works for a little while. And even if you are successful in sticking to an extreme diet, you may end up gaining it all back once you go off it. This is mainly because short-term diets can promote a lot of water loss (not just fat loss). In addition, depending on how long these diets persist, they can do a number on your hunger-regulating hormones, mental state, and potentially your metabolism. Crash diets can also be dangerous for certain individuals.
Some of the main issues associated with eating too few calories include:
You Get Really Hangry
Losing weight, in general, can affect your hunger, fullness hormones causing you to feel more hungry, even after you’ve stopped dieting. While going a little hungry can be helpful for weight reduction, being extremely hungry can be downright painful. If you can get past the constant hunger pains, you may also find that crash dieting is making you obsessed with food. Your body is so hungry that food becomes all you think about.
Being hungry all the time is bad enough, but very-low-calorie diets can cause you to be in a terrible mood as well. Calories, especially carbs, play a major role in regulating your emotions, and being so hungry that you are angry is a real thing. Carbohydrates are linked to your self-control - which is why we cannot control our temper when we have low blood sugar, and we get hangry.
You Get Skinny Fat
If you aren't getting enough protein, and not strength training regularly, extremely restrictive diets may cause you to start burning more lean muscle for energy instead of fat. Why does this matter? You are losing precious muscle mass - which is key for keeping your metabolism intact and improves your overall quality of life. In addition, reduced lean muscle mass increases your overall body fat percentage, even though the number on the scale is decreasing.
Muscle is denser than fat, which can make you look leaner overall. Once you reach your desired weight, you may not feel as fit and toned as you would if you lost more fat and maintained your lean mass throughout the process. In order to decrease your body fat and get toned, you would have to gain muscle mass, essentially gain the weight back, and try to lean out by burning fat. It is pretty counter-intuitive to drop pounds from losing muscle weight just to try and gain back more muscle weight in the end.
Your Workouts Suck
Without the proper fuel, you might find that exercising is extremely difficult or darn near impossible. This matters because physical activity is one way to help increase your calorie burn. In addition, strength training is key to maintaining your precious lean mass while cutting. Not to mention, trying to train on low energy can lead to light-hotheadedness and possible injury if you aren't careful.
Your Nutrition Suffers
The thing is, your body isn't a calculator. And while it needs a daily dose of energy to keep surviving, it also needs proper nutrition to function properly. It is nearly impossible to get all the nutrients your body needs on a very low-calorie diet, even if you're eating only healthy food.
Minor deficiencies can create serious complications. Very low-calorie diets have been linked to heart problems, dehydration, mental confusion, and decreased immune function. And starving yourself over longer periods of time can lead to heart attacks, impaired liver and kidney function, seizures and death (4,5,6).
It Slows Down Your Metabolism
Restrictive diets have been thought to negatively impact your metabolism temporarily by slowing down your natural calorie burn and messing with your ability to resume a normal maintenance diet once you stop dieting. Even though this phenomenon is typically short-lived, it becomes more of a concern if you are constantly jumping from one diet to the next.